07 Dec 11:14
by Yunpeng Qin,
Ye Xu,
Zhengxing Peng,
Jianhui Hou,
Harald Ade
A clear solid‐state aggregation transition of the acceptor N3 is discovered, which enables a double‐annealing method that can fine‐tune aggregation and morphology. Compared with the 16.6% efficiency for PM6:N3:PC71BM‐control devices, a higher efficiency of 17.6% is obtained through the improved protocol. The results provide a molecular design and engineering conundrum to achieve simultaneously low annealing temperatures, high efficiency, and stability.
Abstract
Thermal transition of organic solar cells (OSCs) constituent materials are often insufficiently researched, resulting in trial‐and‐error rather than rational approaches to annealing strategies to improve domain purity to enhance the power conversion efficiency. Despite the potential utility, little is known about the thermal transitions of the modern high‐performance acceptors Y6 and N3. Here, by using an optical method, it is discovered that the acceptor N3 has a clear solid‐state aggregation transition at 82 °C. This unusually low transition not only explains prior optimization protocols, but the transition informs and enables a double‐annealing method that can fine‐tune aggregation and the device morphology. Compared with 16.6% efficiency for PM6:N3:PC71BM control devices, higher efficiency of 17.6% is obtained through the improved protocol. Morphology characterization with x‐ray scattering methods reveals the formation of a multilength scale morphology. Moreover, the double‐annealing method is illustrated and easily transferred and validated with Y6‐based devices, using the transition of Y6 at 102 °C. As a result, the PCE improved from 16.0% to 16.8%. Design of high‐performance acceptors with yet lower aggregation transitions might be required for OSCs to successfully transition to low thermal budget industrial processing methods where annealing temperatures on plastic substrates have to be kept low.
07 Dec 11:14
by Antonio Agresti,
Beatrice Berionni Berna,
Sara Pescetelli,
Alexandro Catini,
Francesca Menchini,
Corrrado Di Natale,
Roberto Paolesse,
Aldo Di Carlo
The novel use of cheap copper‐based corrole as hole transporting material in perovskite solar cells is shown by improving the device thermal stability of n–i–p mesoscopic architecture under prolonged 85 °C stress conditions. Corrole‐based devices show a remarkable power conversion efficiency above 16% by retaining more than 65% of the initial power conversion efficiency after 1000 h of thermal stress.
Abstract
Perovskite solar cells (PSCs) represent nowadays a promising starting point to develop a new efficient and low‐cost photovoltaic technology due to the demonstrated power conversion efficiency (PCE) exceeding 25% on small area devices. However, best reported devices suffer from stability issue under real working conditions thus slowing down the race for the commercialization. In particular, the hole transporting material commonly employed in mesoscopic n–i–p PSCs (nip‐mPSCs), namely spiro‐OMeTAD, is strongly corrupted when subjected to temperatures above 70 °C due to intrinsic thermal instability and because of the dopant employed to improve the hole mobility. In this work, the novel use of a copper‐based corrole as HTM is proposed to improve the device thermal stability of nip‐mPSCs under prolonged 85 °C stress conditions. Corrole‐based devices show remarkable PCE above 16% by retaining more than 65% of the initial PCE after 1000 h of thermal stress, while spiro‐OMeTAD cells abruptly lose more than 60% after the first 40 h. Once scaled‐up to large area modules, the proposed device structure can truly represent a possible way to pass thermal stress tests proposed by IEC‐61646 standards and, not less importantly, the high temperature required by the lamination process for panel production.
01 Dec 01:19
by Mengying Li, Haibo Li, Jing Fu, Tianyu Liang, and Wei Ma
The Journal of Physical Chemistry C
DOI: 10.1021/acs.jpcc.0c08019
01 Dec 01:10
by Yongtao Liu,
Anton V. Ievlev,
Nikolay Borodinov,
Matthias Lorenz,
Kai Xiao,
Mahshid Ahmadi,
Bin Hu,
Sergei V. Kalinin,
Olga S. Ovchinnikova
Using time‐resolved time‐of‐flight secondary ion mass spectrometry (tr‐ToF‐SIMS), electric field and light induced ion migration in hybrid organic‐inorganic perovskites are directly observed, revealing the migration behavior of methylammonium and halides. It is found that light‐induced methylammonium migration is more significant. In addition, the light with sub‐bandgap energy cannot induce ion migration.
Abstract
Unique optoelectronic, electronic, and sensing properties of hybrid organic–inorganic perovskites (HOIPs) are underpinned by the complex interactions between electronic and ionic states. Here, the photoinduced field ion migration in HOIPs is directly observed. Using newly developed local probe time‐resolved techniques, more significant CH3NH3
+ migration than I−/Br− migration in HOIPs is unveiled. It is found that light illumination only induces CH3NH3
+ migration but not I−/Br− migration. By directly observing temporal changes in bias‐induced and photoinduced ion migration in device conditions, it is revealed that light illumination suppresses the bias‐induced ion redistribution in the lateral device. These findings, being a necessary compensation of previous understandings of ion migration in HOIPs based on simulations and static and/or indirect measurements, offer advanced insights into the distinct light effects on the migration of organic cation and halides in HOIPs, which are expected to be helpful for improving the performance and the long‐term stability of HOIPs optoelectronics.
01 Dec 01:10
by Pu Fan,
Wenjian Sun,
Xiaohua Zhang,
Yao Wu,
Qin Hu,
Qing Zhang,
Junsheng Yu,
Thomas P. Russell
The photoinitiator bifunctional bis‐benzophenone is introduced into non‐fullerene solar cells as a multifunctional solid additive for the first time. The doping of this solid additive could not only modify the polymer order and firm morphology of active layer to improve device performance, but also to achieve better reproducibility, thickness insensitivity, and thermal stability for the non‐fullerene solar cells.
Abstract
Simultaneously improving efficiency and stability is critical for the commercial application of non‐fullerene acceptor polymer solar cells (NFA‐PSCs). Multifunctional solid additives have been considered as a potential route to tune the morphology of the active layer and optimize performance. In this work, photoinitiator bifunctional bis‐benzophenone (BP‐BP) is used as a solid additive, replacing solvent additives, in the PBDB‐T:ITIC NFA system. With the addition of BP‐BP, the intermolecular π–π stacking of PBDB‐T and morphology is improved, leading to more balanced carrier transport and more effective exciton dissociation. Devices fabricated with BP‐BP show a power conversion efficiency (PCE) of 11.89%, with enhanced short‐circuit current (J
sc), and fill factor (FF). Devices optimized with BP‐BP show excellent reproducibility, insensitivity to thickness, and an improved thermal stability under atmospheric conditions without encapsulation. This work provides a new strategy for the application of solid additives in NFA‐PSCs.
25 Nov 08:39
by Chi‐Lun Mai,
Qin Zhou,
Qiu Xiong,
Ching‐Chin Chen,
Jianbin Xu,
Zhuangzhuang Zhang,
Hsuan‐Wei Lee,
Chen‐Yu Yeh,
Peng Gao
A series of Donor–π–Acceptor porphyrins coded as CS0, CS1, and CS2 that can effectively passivate the perovskite surface, increase V
OC and FF, reduce the hysteresis effect, enhance power conversion efficiency to be higher than 22%, and improve the device stability have been developed.
Abstract
In recent years, hybrid perovskite solar cells (PSCs) have attracted much attention owing to their low cost, easy fabrication, and high photoelectric conversion efficiency. Nevertheless, solution‐processed perovskite films usually show substantial structural disorders, resulting in ion defects on the surface of lattice and grain boundaries. Herein, a series of D–π–A porphyrins coded as CS0, CS1, and CS2 that can effectively passivate the perovskite surface, increase V
OC and FF, reduce the hysteresis effect, enhance power conversion efficiency to be higher than 22%, and improve the device stability is developed. The results in this study demonstrated that the donor–π–acceptor type porphyrin derivatives are promising passivators that can improve the cell performance of PSCs.
21 Nov 01:40
by Kaimo Deng,
Qinghua Chen,
Liang Li
SnO2 has been applied as an efficient electron transport layer for perovskite solar cells over the past few years. In this progress report, recent advances in SnO2 modification toward high efficiency and stability are summarized from the perspective of the optimization strategies, and the remaining challenges as well as opportunities for future research are also discussed.
Abstract
The electron transport layer plays a key role in affecting the charge dynamics and photovoltaic parameters in perovskite solar cells. Compared to other counterparts, SnO2 has unique advantages such as low temperature fabrication and high electron extraction ability, and it receives extra attentions from the research community since the first report. Planar‐type perovskite solar cells based on SnO2 exhibit a simple architecture and state of art device can achieve a power conversion efficiency of over 23%, which can compete with traditional devices using mesoporous TiO2. The modification engineering of SnO2 has contributed significantly to the enhanced device performance during the past years. There is still great potential for further improvement in the efficiency and long‐term stability. Herein recent advances toward modifying the optoelectronic properties of SnO2 from the perspective of the optimization strategies are summarized and the remaining challenges as well as opportunities for future research are discussed. The continuous efforts dedicated to this exciting field may pave the way for developing commercial perovskite solar cells.
21 Nov 01:39
by Antonio Agresti,
Beatrice Berionni Berna,
Sara Pescetelli,
Alexandro Catini,
Francesca Menchini,
Corrrado Di Natale,
Roberto Paolesse,
Aldo Di Carlo
The novel use of cheap copper‐based corrole as hole transporting material in perovskite solar cells is shown by improving the device thermal stability of n–i–p mesoscopic architecture under prolonged 85 °C stress conditions. Corrole‐based devices show a remarkable power conversion efficiency above 16% by retaining more than 65% of the initial power conversion efficiency after 1000 h of thermal stress.
Abstract
Perovskite solar cells (PSCs) represent nowadays a promising starting point to develop a new efficient and low‐cost photovoltaic technology due to the demonstrated power conversion efficiency (PCE) exceeding 25% on small area devices. However, best reported devices suffer from stability issue under real working conditions thus slowing down the race for the commercialization. In particular, the hole transporting material commonly employed in mesoscopic n–i–p PSCs (nip‐mPSCs), namely spiro‐OMeTAD, is strongly corrupted when subjected to temperatures above 70 °C due to intrinsic thermal instability and because of the dopant employed to improve the hole mobility. In this work, the novel use of a copper‐based corrole as HTM is proposed to improve the device thermal stability of nip‐mPSCs under prolonged 85 °C stress conditions. Corrole‐based devices show remarkable PCE above 16% by retaining more than 65% of the initial PCE after 1000 h of thermal stress, while spiro‐OMeTAD cells abruptly lose more than 60% after the first 40 h. Once scaled‐up to large area modules, the proposed device structure can truly represent a possible way to pass thermal stress tests proposed by IEC‐61646 standards and, not less importantly, the high temperature required by the lamination process for panel production.
21 Nov 00:54
by Chi‐Lun Mai,
Qin Zhou,
Qiu Xiong,
Ching‐Chin Chen,
Jianbin Xu,
Zhuangzhuang Zhang,
Hsuan‐Wei Lee,
Chen‐Yu Yeh,
Peng Gao
A series of Donor–π–Acceptor porphyrins coded as CS0, CS1, and CS2 that can effectively passivate the perovskite surface, increase V
OC and FF, reduce the hysteresis effect, enhance power conversion efficiency to be higher than 22%, and improve the device stability have been developed.
Abstract
In recent years, hybrid perovskite solar cells (PSCs) have attracted much attention owing to their low cost, easy fabrication, and high photoelectric conversion efficiency. Nevertheless, solution‐processed perovskite films usually show substantial structural disorders, resulting in ion defects on the surface of lattice and grain boundaries. Herein, a series of D–π–A porphyrins coded as CS0, CS1, and CS2 that can effectively passivate the perovskite surface, increase V
OC and FF, reduce the hysteresis effect, enhance power conversion efficiency to be higher than 22%, and improve the device stability is developed. The results in this study demonstrated that the donor–π–acceptor type porphyrin derivatives are promising passivators that can improve the cell performance of PSCs.
13 Nov 01:28
by Zhu Ma, Weiya Zhou, Dejun Huang, Qianyu Liu, Zheng Xiao, Huifeng Jiang, Zhiqing Yang, Wenfeng Zhang, and Yuelong Huang
ACS Applied Materials & Interfaces
DOI: 10.1021/acsami.0c12030
12 Nov 04:02
by Shuyan Liang, Zhigang Lou, Qilin Zhang, Yalong Xu, Feng Jin, Jianyu Yuan, Chuanxiang Sheng, Wanli Ma, and Haibin Zhao
The Journal of Physical Chemistry C
DOI: 10.1021/acs.jpcc.0c08559
12 Nov 04:02
by Byung Gi Kim, Woongsik Jang, Yu Jung Park, Ju Hwan Kang, Jung Hwa Seo, and Dong Hwan Wang
The Journal of Physical Chemistry C
DOI: 10.1021/acs.jpcc.0c05804
12 Nov 03:29
by Taimoor Ahmad,
Barbara Wilk,
Eros Radicchi,
Rosinda Fuentes Pineda,
Pierpaolo Spinelli,
Jan Herterich,
Luigi Angelo Castriotta,
Shyantan Dasgupta,
Edoardo Mosconi,
Filippo De Angelis,
Markus Kohlstädt,
Uli Würfel,
Aldo Di Carlo,
Konrad Wojciechowski
Solution‐processed fullerene derivative, [6,6]‐phenyl‐C61 butyric acid n‐hexyl ester, is reported as an effective electron transport material in perovskite solar cells. It allows smooth capping of the perovskite surface, resulting in high efficiencies, reaching 18.4% for large‐area, flexible devices. Furthermore, compared to other fullerenes, it shows reduced recombination losses at the interface with perovskite and facile scalability with the ink‐jet printing technique.
Abstract
Metal halide perovskites have raised huge excitement in the field of emerging photovoltaic technologies. The possibility of fabricating perovskite solar cells (PSCs) on lightweight, flexible substrates, with facile processing methods, provides very attractive commercial possibilities. Nevertheless, efficiency values for flexible devices reported in the literature typically fall short in comparison to rigid, glass‐based architectures. Here, a solution‐processable fullerene derivative, [6,6]‐phenyl‐C61 butyric acid n‐hexyl ester (PCBC6), is reported as a highly efficient alternative to the commonly used n‐type materials in perovskite solar cells. The cells with the PCBC6 layer deliver a power conversion efficiency of 18.4%, fabricated on a polymer foil, with an active area of 1 cm2. Compared to the phenyl‐C61‐butyric acid methyl ester benchmark, significantly enhanced photovoltaic performance is obtained, which is primarily attributed to the improved layer morphology. It results in a better charge extraction and reduced nonradiative recombination at the perovskite/electron transporting material interface. Solution‐processed PCBC6 films are uniform, smooth and displayed conformal capping of perovskite layer. Additionally, a scalable processing of PCBC6 layers is demonstrated with an ink‐jet printing technique, producing flexible PSCs with efficiencies exceeding 17%, which highlights the prospects of using this material in an industrial process.
12 Nov 03:00
by Furui Tan,
Makhsud I. Saidaminov,
Hairen Tan,
James Z. Fan,
Yuhang Wang,
Shizhong Yue,
Xiaotian Wang,
Zhitao Shen,
Shengjun Li,
Junhwan Kim,
Yueyue Gao,
Gentian Yue,
Rong Liu,
Ziru Huang,
Chen Dong,
Xiaodong Hu,
Weifeng Zhang,
Zhijie Wang,
Shengchun Qu,
Zhanguo Wang,
Edward H. Sargent
A bilinkable contact passivation strategy is developed for modifying charge kinetics at the charge transport layer:active layer interface in solar cells. The use of the bifunctional molecule 3‐thiophenecarboxylic acid (TCA) passivates undercoordinated Ti (ETL‐side) and Pb (perovskite‐side), enabling efficient electron extraction through the interface. TCA‐treated films show an increase of PCE of 21.2% compared to 19.8% for reference devices.
Abstract
Charge recombination due to interfacial defects is an important source of loss in perovskite solar cells. Here, a two‐sided passivation strategy is implemented by incorporating a bilinker molecule, thiophene‐based carboxylic acid (TCA), which passivates defects on both the perovskite side and the TiO2 side of the electron‐extracting heterojunction in perovskite solar cells. Density functional theory and ultrafast charge dynamics reveal a 50% reduction in charge recombination at this interface. Perovskite solar cells made using TCA‐passivated heterojunctions achieve a power conversion efficiency of 21.2% compared to 19.8% for control cells. The TCA‐containing cells retain 96% of initial efficiency following 50 h of UV‐filtered MPP testing.
12 Nov 01:11
by Fumin Li,
Zhitao Shen,
Yujuan Weng,
Qiang Lou,
Chong Chen,
Liang Shen,
Wenbin Guo,
Guangyong Li
An N‐type semiconductor material, (CH3)2Sn(COOH)2 (CSCO), is prepared for the first time as an electron transport layer for n‐i‐p planar perovskite solar cells, which leads to one of the highest power conversion efficiencies of 22.21%, and to remarkable stability, retaining over 83% of its initial power conversion efficiency without encapsulation after 130 days of storage in ambient conditions.
Abstract
The electron transport layer (ETL) has an important influence on the power conversion efficiency (PCE) and stability of n‐i‐p planar perovskite solar cells (PSCs). This paper presents an N‐type semiconductor material, (CH3)2Sn(COOH)2 (abbreviated as CSCO) that is synthesized and prepared for the first time as an ETL for n‐i‐p planar PSCs, which leads to a high PCE of 22.21% after KCl treatment, one of the highest PCEs of n‐i‐p planar PSCs to date. Further analysis reveals that the high PCE is attributed to the excellent conductivity of CSCO because of its more delocalized electron cloud distribution due to its unique −O=C−O− group, and to the defect passivation of the Cs0.05(FA0.85MA0.15)0.95Pb(I0.85Br0.15)3 (denoted as CsFAMA) perovskite through the interaction between the O (Sn) atoms of CSCO and the Pb (halogen) atoms of CsFAMA at CSCO/CsFAMA interface, while the traditional ETL materials such as SnO2 film lack this function. In addition to the high PCE, the optimal PSCs using CSCO as ETL show remarkable stability, retaining over 83% of its initial PCE without encapsulation after 130 days of storage in ambient conditions (≈25 °C at ≈40% humidity), much better than the traditional SnO2‐based n‐i‐p PSCs.
12 Nov 00:58
by Minhuan Wang,
Shaun Tan,
Yepin Zhao,
Pengchen Zhu,
Yanfeng Yin,
Yulin Feng,
Tianyi Huang,
Jingjing Xue,
Rui Wang,
Gill Sang Han,
Hyun Suk Jung,
Jiming Bian,
Jin‐Wook Lee,
Yang Yang
An in‐situ formed polymeric interlayer enables enhanced photovoltaic performance of the methylammonium‐, cesium‐, and bromide‐free perovskite solar cells with superior photo‐ and thermal‐stability. The polymeric interlayer promotes growth of perovskite crystals with reduced defect density and improves the contact between the perovskite and hole transporting layers to assists in photo‐excited charge extraction.
Abstract
The vast majority of high‐performance perovskite solar cells (PSCs) are based on multi‐cation mixed‐anion compositions incorporating methylammonium (MA) and bromide (Br). Nevertheless, the thermal instability of MA and the tendency of mixed halide compositions to phase segregate limit the long‐term stability of PSCs. However, reports of MA‐free and/or Br‐free compositions are rare in the community since their performance is generally inferior. Here, a strategy is presented to achieve highly efficient and stable PSCs that are altogether cesium (Cs)‐free, MA‐free and Br‐free. An antisolvent quenching process is used to in‐situ deposit a polymeric interlayer to promote the growth of phase‐pure formamidinium lead tri‐iodide perovskite crystals with reduced defect density and to assist in photo‐excited charge extraction. The PSCs developed are among the best‐performing reported for such compositions. Moreover, the PSCs show superior stability under continuous exposure to both illumination and 85 °C heat.
12 Nov 00:57
by Yuan Cai,
Jian Cui,
Ming Chen,
Miaomiao Zhang,
Yu Han,
Fang Qian,
Huan Zhao,
Shaomin Yang,
Zhou Yang,
Hongtao Bian,
Tao Wang,
Kunpeng Guo,
Molang Cai,
Songyuan Dai,
Zhike Liu,
Shengzhong (Frank) Liu
Aided by theoretical calculation, a multifunctional 2,2‐difluoropropanediamide (DFPDA) molecule that bears carbonyl, amino, and fluorine groups is first introduced into the perovskite precursor, serving as a crystal growth mitigator, grain boundaries passivator, and surface protection material. With the help of the combined effects of multifunctional groups in DFPDA, the perovskite cells deliver an efficiency of 22.21% and improved stability.
Abstract
With a certified efficiency as high as 25.2%, perovskite has taken the crown as the highest efficiency thin film solar cell material. Unfortunately, serious instability issues must be resolved before perovskite solar cells (PSCs) are commercialized. Aided by theoretical calculation, an appropriate multifunctional molecule, 2,2‐difluoropropanediamide (DFPDA), is selected to ameliorate all the instability issues. Specifically, the carbonyl groups in DFPDA form chemical bonds with Pb2+ and passivate under‐coordinated Pb2+ defects. Consequently, the perovskite crystallization rate is reduced and high‐quality films are produced with fewer defects. The amino groups not only bind with iodide to suppress ion migration but also increase the electron density on the carbonyl groups to further enhance their passivation effect. Furthermore, the fluorine groups in DFPDA form both an effective barrier on the perovskite to improve its moisture stability and a bridge between the perovskite and HTL for effective charge transport. In addition, they show an effective doping effect in the HTL to improve its carrier mobility. With the help of the combined effects of these groups in DFPDA, the PSCs with DFPDA additive achieve a champion efficiency of 22.21% and a substantially improved stability against moisture, heat, and light.
07 Nov 00:58
by Yuan Cai,
Jian Cui,
Ming Chen,
Miaomiao Zhang,
Yu Han,
Fang Qian,
Huan Zhao,
Shaomin Yang,
Zhou Yang,
Hongtao Bian,
Tao Wang,
Kunpeng Guo,
Molang Cai,
Songyuan Dai,
Zhike Liu,
Shengzhong (Frank) Liu
Aided by theoretical calculation, a multifunctional 2,2‐difluoropropanediamide (DFPDA) molecule that bears carbonyl, amino, and fluorine groups is first introduced into the perovskite precursor, serving as a crystal growth mitigator, grain boundaries passivator, and surface protection material. With the help of the combined effects of multifunctional groups in DFPDA, the perovskite cells deliver an efficiency of 22.21% and improved stability.
Abstract
With a certified efficiency as high as 25.2%, perovskite has taken the crown as the highest efficiency thin film solar cell material. Unfortunately, serious instability issues must be resolved before perovskite solar cells (PSCs) are commercialized. Aided by theoretical calculation, an appropriate multifunctional molecule, 2,2‐difluoropropanediamide (DFPDA), is selected to ameliorate all the instability issues. Specifically, the carbonyl groups in DFPDA form chemical bonds with Pb2+ and passivate under‐coordinated Pb2+ defects. Consequently, the perovskite crystallization rate is reduced and high‐quality films are produced with fewer defects. The amino groups not only bind with iodide to suppress ion migration but also increase the electron density on the carbonyl groups to further enhance their passivation effect. Furthermore, the fluorine groups in DFPDA form both an effective barrier on the perovskite to improve its moisture stability and a bridge between the perovskite and HTL for effective charge transport. In addition, they show an effective doping effect in the HTL to improve its carrier mobility. With the help of the combined effects of these groups in DFPDA, the PSCs with DFPDA additive achieve a champion efficiency of 22.21% and a substantially improved stability against moisture, heat, and light.
06 Nov 00:47
by Congcong Wu,
Kai Wang,
Yuanyuan Jiang,
Dong Yang,
Yuchen Hou,
Tao Ye,
Chan Su Han,
Bo Chi,
Li Zhao,
Shimin Wang,
Weiwei Deng,
Shashank Priya
An electrospray printing technique is developed to continuously print the TiO2 electron transport layer, perovskite layer, and carbon layer, enabling a cost‐effective device. The electrospray technique is capable of printing uniform, compact, and high adhesion layers with controllable dimensions and patterns. This work demonstrates a fully printed low‐cost solar cell and provides a feasible process for perovskite solar cells to initial industrialization.
Abstract
With the power conversion efficiencies of perovskite solar cells (PSCs) exceeding 25%, the PSCs are a step closer to initial industrialization. Prior to transferring from laboratory fabrication to industrial manufacturing, issues such as scalability, material cost, and production line compatibility that significantly impact the manufacturing remain to be addressed. Here, breakthroughs on all these fronts are reported. Carbon‐based PSCs with architecture fluorine doped tin oxide (FTO)/electron transport layer/perovskite/carbon, that eliminate the need for the hole transport layer and noble metal electrode, provide ultralow‐cost configuration. This PSC architecture is manufactured using a scalable and industrially compatible electrospray (ES) technique, which enables continuous printing of all the cell layers. The ES deposited electron transport layer and perovskite layer exhibit properties comparable to that of the laboratory‐scale spin coating method. The ES deposited carbon electrode layer exhibits superior conductivity and interfacial microstructure in comparison to films synthesized using the conventional doctor blading technique. As a result, the fully ES printed carbon‐based PSCs show a record 14.41% power conversion efficiency, rivaling the state‐of‐the‐art hole transporter‐free PSCs. These results will immediately have an impact on the scalable production of PSCs.
01 Nov 05:16
by Ivan Sudakov,
Melissa Van Landeghem,
Ruben Lenaerts,
Wouter Maes,
Sabine Van Doorslaer,
Etienne Goovaerts
Nonfullerene acceptors offer new opportunities for high efficiencies in organic solar cells, but the suppression of photodegradation of the materials in the presence of dioxygen is essential. The complex behavior of the reactive oxygen species superoxide and singlet oxygen in the degradation of the donor polymer poly(3‐hexylthiophene), the small molecule acceptor 5,5′‐[(9,9‐dioctyl‐9H‐fluorene‐2,7‐diyl)bis(2,1,3‐benzothiadiazole‐7,4‐diylmethylidyne)]bis[3‐ethyl‐2‐thioxo‐4‐thiazolidinone], and their blends is unraveled in detail.
Abstract
With rapid advances in material synthesis and device performance, the long‐term stability of organic solar cells has become the main remaining challenge toward commercialization. An investigation of photodegradation in blend films of the donor polymer poly(3‐hexylthiophene) (P3HT) and the rhodanine‐flanked small molecule acceptor 5,5′‐[(9,9‐dioctyl‐9H‐fluorene‐2,7‐diyl)bis(2,1,3‐benzothiadiazole‐7,4‐diylmethylidyne)]bis[3‐ethyl‐2‐thioxo‐4‐thiazolidinone] (FBR) is presented in an ambient atmosphere. The photobleaching kinetics of the pure materials and their blends is correlated with the generation of radicals and triplet excitons using optical and magnetic resonance techniques. In addition, spin‐trapping methods are employed to identify reactive oxygen species (ROS). In films of P3HT, FBR, and the P3HT:FBR blend, superoxide is generated by electron transfer to molecular oxygen. However, it is found that the generation of singlet oxygen by energy transfer from the FBR triplet state is responsible for the poor stability of FBR and for the accelerated photodegradation at later times of the P3HT:FBR blend. In the early stage of degradation of the neat blend, it is protected from singlet oxygen by the fast donor–acceptor charge transfer, which competes with triplet exciton formation. These results provide initial input for a rational design of donor and acceptor materials through tuning the molecular singlet and triplet energy levels to prevent ROS‐related photodegradation.
01 Nov 05:16
by Hanjian Lai,
Feng He
The relationship between structure design, packing arrangement, and molecular property of organic photovoltaic (OPV) acceptors is explored, in which the 3D network packing originating from non‐covalent intermolecular interactions and aggregation states, is found to promote OPV device performance. This review sheds light on charge transport processes in acceptors and provides a guideline for developing new generation OPV materials.
Abstract
The power conversion efficiency of organic solar cell (OSC) devices has surpassed 18% rapidly. In order to further promote OSC development, it is necessary to understand the packing information at the atomic level to help develop acceptor systems with superior performance. The packing arrangements and intermolecular interactions of these acceptors in the solid state, observed by single crystal X‐ray crystallography, are often used to design materials with expected physicochemical properties. In this review, the chemical structures of acceptors revealed by single crystal X‐ray crystallography are summarized, and the relationship between structural design, packing arrangement, and device properties is discussed. In addition, the concept of “3D network packing” in acceptor systems is proposed, which offers better charge transfer properties in reported chlorinated, fluorinated, brominated, and trifluoromethylated systems, an understanding of 3D network transport also provides guidance in high‐performance materials design. Finally, some current issues related to single crystal studies in OSCs are discussed, with an emphasis on the significance of developing acceptors by understanding and adjusting the aggregation states and intermolecular interactions of materials by single crystal analysis.
01 Nov 05:15
by Donghwan Koo,
Yongjoon Cho,
Ungsoo Kim,
Gyujeong Jeong,
Junghyun Lee,
Jihyung Seo,
Changduk Yang,
Hyesung Park
A newly conceived n‐type small molecule (Y‐Th2) is incorporated as an efficient additive in perovskite solar cells, achieving simultaneous improvements in device performance and stability. Y‐Th2 effectively passivates defects in perovskite crystals by Lewis acid–base interactions and intermolecular hydrogen bonds, obtaining high‐quality perovskite film. The inverted structure device exhibits a power conversion efficiency of 21.5% with notably enhanced operational stability.
Abstract
Significant efforts have been devoted to modulating the grain size and improving the film quality of perovskite in perovskite solar cells (PSCs). Adding materials to the perovskite is especially promising for high‐performance PSCs, because the additives effectively control the crystal structure. Although the additive engineering approach has substantially boosted the efficiency of PSCs, instability of the perovskite film has remained a primary bottleneck for the commercialization of PSCs. Herein, a newly conceived bithiophene‐based n‐type conjugated small molecule (Y‐Th2) is introduced to PSCs, which simultaneously enhances the performance and stability of the cell. The Y‐Th2 effectively passivates the defect states in perovskite through Lewis acid–base interactions, increasing the grain size and quality of the perovskite absorber. An inverted PSC containing the Y‐Th2 additive achieves a power conversion efficiency of 21.5%, versus 18.3% in the reference device. The operational stability is also considerably enhanced by the improved hydrophobicity and intermolecular hydrogen bonds in the perovskite.
01 Nov 05:02
by Shaomin Yang,
Weiduan Liu,
Yu Han,
Zhike Liu,
Wenjing Zhao,
Chenyang Duan,
Yuhang Che,
Haoshuang Gu,
Yuebin Li,
Shengzhong (Frank) Liu
Herein, novel Ruddlesden–Popper Cs2PbI2Cl2 nanosheets are synthesized and creatively employed as a multifunctional interface optimization material to improve the performance of CsPbI2Br solar cells. Based on the heterostructured NSs/CsPbI2Br/NSs inorganic film, an efficiency of 16.65% is obtained, which is one of the best reported for CsPbI2Br solar cells, along with much‐enhanced UV, air, and thermal stabilities.
Abstract
Inorganic CsPbI2Br perovskite solar cells (PSCs) have gained enormous research interest due to their excellent thermal and light stabilities. However, their unsatisfactory power‐conversion efficiency and poor intrinsic phase stability remain roadblocks to their further development. Herein, Cs2PbI2Cl2 nanosheets (NSs) with the Ruddlesden–Popper (RP) structure are synthesized, and an NSs/CsPbI2Br/NSs heterostructure is employed to enhance both the stability and efficiency of CsPbI2Br solar cells. The novel Cs2PbI2Cl2 NSs can not only passivate the top and bottom surfaces of the perovskite film and top surface of the TiO2 film but also enhance the stability of the perovskite film. Based on the heterostructured NSs/CsPbI2Br/NSs inorganic perovskite film, the efficiency of the CsPbI2Br PSCs is improved from 15.02% to 16.65%. Moreover, the unencapsulated CsPbI2Br devices with the NSs/CsPbI2Br/NSs heterostructure sustain over 90% of their original efficiencies after being exposed to ambient conditions (≈25 °C and ≈35% RH) for 648 h. Both the UV‐light‐soaking stability (100 mW cm−1 365 nm UV light) and thermal stability (T = 85 °C) of the optimized devices are dramatically improved in comparison with their counterparts with only a 3D active layer. Therefore, this work promotes the application of RP inorganic perovskite nanocrystals in a range of perovskite optoelectronic devices.
01 Nov 02:00
by Xiao Kang△, Xiaoming Li△, Haining Liu, Zezhou Liang, Weichao Chen, Nan Zheng, Shanlin Qiao, and Renqiang Yang
ACS Applied Materials & Interfaces
DOI: 10.1021/acsami.0c10658
01 Nov 01:59
by Guilong Cai, Yuhao Li, Jiadong Zhou, Peiyao Xue, Kuan Liu, Jiayu Wang, Zengqi Xie, Gang Li, Xiaowei Zhan, and Xinhui Lu
ACS Applied Materials & Interfaces
DOI: 10.1021/acsami.0c14612
01 Nov 01:59
by Samala Venkateswarlu, Yan-Duo Lin, Kun-Mu Lee, Kang-Ling Liau, and Yu-Tai Tao
ACS Applied Materials & Interfaces
DOI: 10.1021/acsami.0c15676
01 Nov 01:59
by Menglei Feng, Ming Wang, Hongpeng Zhou, Wei Li, Shuangpeng Wang, Zhigang Zang, and Shijian Chen
ACS Applied Materials & Interfaces
DOI: 10.1021/acsami.0c15923
01 Nov 01:48
by Sheng Li, Fei Qin, Qi Peng, Shuang Liu, Zhihui Zhang, Deyi Zhang, Chao Liu, Daiyu Li, Jiale Liu, Jianhang Qi, Yue Hu, Yaoguang Rong, Anyi Mei, and Hongwei Han
Nano Letters
DOI: 10.1021/acs.nanolett.0c03286
28 Oct 00:50
by Qiang Luo,
Ronggen Wu,
Lantian Ma,
Chaojun Wang,
Hu Liu,
Hong Lin,
Ning Wang,
Yuan Chen,
Zhanhu Guo
Recent progress concerning the uses of carbon nanotubes (CNTs) as transparent conductive electrodes, charge‐transporter, perovskite additives, interlayers, hole‐transporting materials, and back electrodes in perovskite solar cells (PSCs) is reviewed. The application of CNTs toward the development of 1D and 2D flexible PSCs is discussed. Current challenges and prospective on research directions of employing CNTs to realize high‐performance PSCs is presented.
Abstract
Metal halide perovskite solar cells (PSCs) have emerged as promising next‐generation photovoltaic devices with the maximum output efficiency exceeding 25%. Despite significant advances, there are many challenges to achieve high efficiency, stability, and low‐cost simultaneously. Combating these challenges depends on developing novel materials and modifying conventional device components. Carbon nanotubes (CNTs) have attracted considerable attention for fabricating efficient PSCs owing to their remarkable electrical, optical, and mechanical properties. With their multifunctional features, CNTs can play a wide range of roles and offer unique benefits in various components in PSCs to improve device performance and durability. Here, recent progress concerning the utilizations of CNTs as transparent conductive electrodes, charge‐transporter, perovskite additives, interlayers, hole‐transporting materials, and back electrodes in PSCs is comprehensively reviewed. The application of CNTs toward the development of 1D and 2D flexible PSCs is also discussed. A summary of current challenges and prospective on future research directions of employing CNTs to realize high‐performance PSCs is presented.
28 Oct 00:43
by Fengyou Wang,
Yuhong Zhang,
Meifang Yang,
Donglai Han,
Lili Yang,
Lin Fan,
Yingrui Sui,
Yunfei Sun,
Xiaoyan Liu,
Xiangwei Meng,
Jinghai Yang
Novel interface polarization induced field‐effect passivation based on amorphous transition metal oxide is developed for efficient and ambient‐air‐stable perovskite solar cells. Comprehensive insights into the interaction between the field‐effect passivation, interface polarities, and the performance of the device have been elucidated in detail.
Abstract
Organolead halide hybrid perovskite solar cells (PSCs) have become a shining star in the renewable devices field due to the sharp growth of power conversion efficiency; however, interfacial recombination and carrier‐extraction losses at heterointerfaces between the perovskite active layer and the carrier transport layers remain the two main obstacles to further improve the power conversion efficiency. Here, novel field‐effect passivation has been successfully induced to effectively suppress the interfacial recombination and improve interfacial charge transfer by incorporating interfacial polarization via inserting a high work function interlayer between perovskite and holes transport layer. The charge dynamics within the device and the mechanism of the field‐effect passivation are elucidated in detail. The unique interfacial dipoles reinforce the built‐in field and prevent the photogenerated charges from recombining, resulting in power conversion efficiency up to 21.7% with negligible hysteresis. Furthermore, the hydrophobic interlayer also suppresses the perovskite decomposition by preventing the moisture penetration, thereby improving the humidity stability of the PSCs (>91% of the initial power conversion efficiency (PCE) after 30 d in 65 ± 5% humidity). Finally, several promising research perspectives based on field‐effect passivation are also suggested for further conversion efficiency improvements and photovoltaic applications.