Can Li  Yong Wang  Wallace C. H. Choy 《Small Methods》2020,4(7)

Organic–inorganic hybrid perovskite materials are excellent candidates as light absorbers in tandem solar cells with advantages of tunable bandgaps, high absorption coefficients, facile fabrication processes, and low costs. Tandem devices offer a route to further improve the efficiency and reduce the cost for the solar cell practical applications. One critical challenge that limits the development of two‐terminal perovskite‐based tandem devices is the interconnection between two subcells. To achieve efficient interconnection in the tandem devices, it is required to simultaneously fulfill the high electrical, optical, and chemical requirements. In particular, chemical protection requirement is necessary to enable a tandem device in the case of solution‐processed perovskite–perovskite tandem solar cells. In this work, recent advances of interconnection in perovskite‐based two‐terminal tandem solar cells are reviewed. A brief introduction to the topic is first given. The definition, functions, and requirements of interconnecting layers in two‐terminal tandem devices are then discussed. Next, the insights into recent advances of interconnecting layers in two‐terminal perovskite‐based tandem solar cells (perovskite–perovskite, perovskite–polymer, perovskite–inorganic tandem solar cells) are further described. Finally, an outlook of the future research directions and a brief summary are drawn.  相似文献   

    

Luozheng Zhang  Xianyong Zhou  Chang Liu  Xingzhu Wang  Baomin Xu 《Small Methods》2020,4(9)

Perovskite solar cells (PSCs) based on conventional hole‐transporting materials (HTMs) have achieved power conversion efficiencies comparable to those of typical inorganic solar cells; however, the dopants used to increase the hole mobility or the film‐forming ability impart these devices with a poor long‐term stability, blocking the industrial commercialization of PSCs. As an alternative, HTMs without any dopants are explored. Herein, dopant‐free small molecular HTMs (SM‐HTMs) are reviewed and the performance based on the analyses of their molecular structures are evaluated. A summary of the designing principle and an outlook of the development of highly efficient SM‐HTMs are presented.  相似文献   

    

Shikai Yan  Qing Li  Xu Zhang  Sheng Tang  Wei Lei  Jing Chen 《Journal of the Society for Information Display》2020,28(1):9-15

In this work, the vertical structure photodetector based on CsPbBr₃ quantum dots (QDs) with a structure of indium tin oxide (ITO)/zinc oxide (ZnO)/CsPbBr₃ QDs/Au is reported. In this device, CsPbBr₃ QDs film works as the light‐harvesting layer, and ZnO QDs film acts as the electron transport channel, which can extract the electron efficiently and improve the quality of CsPbBr₃ QDs film. As a result, the on/off ratio, detectivity and rise time (decay time) of CsPbBr₃/ZnO hybrid photodetector are measured to be 2.4 × 10⁶, 2.25 × 10¹¹, and 62 milliseconds (82 ms) under 0‐V bias. This work inspires the development of vertical structure photodetectors based on the all‐inorganic perovskite QDs.  相似文献   

    

Pengyang Wang  Renjie Li  Bingbing Chen  Fuhua Hou  Jie Zhang  Ying Zhao  Xiaodan Zhang 《Advanced materials (Deerfield Beach, Fla.)》2020,32(6):1905766

An electron-transport layer (ETL) with appropriate energy alignment and enhanced charge transfer is critical for perovskite solar cells (PSCs). However, interfacial energy level mismatch limits the electrical performance of PSCs, particularly the open-circuit voltage (V_OC). Herein, a simple low-temperature-processed In₂O₃/SnO₂ bilayer ETL is developed and used for fabricating a new PSC device. The presence of In₂O₃ results in uniform, compact, and low-trap-density perovskite films. Moreover, the conduction band of In₂O₃ is shallower than that of Sn-doped In₂O₃ (ITO), enhancing the charge transfer from perovskite to ETL, thus minimizing V_OC loss at the perovskite and ETL interface. A planar PSC with a power conversion efficiency of 23.24% (certified efficiency of 22.54%) is obtained. A high V_OC of 1.17 V is achieved with the potential loss at only 0.36 V. In contrast, devices based on single SnO₂ layers achieve 21.42% efficiency with a V_OC of 1.13 V. In addition, the new device maintains 97.5% initial efficiency after 80 d in N₂ without encapsulation and retains 91% of its initial efficiency after 180 h under 1 sun continuous illumination. The results demonstrate and pave the way for the development of efficient photovoltaic devices.  相似文献   

    

Fei Cao  Jingde Chen  Dejian Yu  Shu Wang  Xiaobao Xu  Jiaxin Liu  Zeyao Han  Bo Huang  Yu Gu  Kwang Leong Choy  Haibo Zeng 《Advanced materials (Deerfield Beach, Fla.)》2020,32(6):1905362

Fluorescence imaging with photodetectors (PDs) toward near-infrared I (NIR-I) photons (700–900 nm), the so-called “optical window” in organisms, has provided an important path for tracing biological processes in vivo. With both excitation photons and fluorescence photons in this narrow range, a stringent requirement arises that the fluorescence signal should be efficiently differentiated for effective sensing, which cannot be fulfilled by common PDs with a broadband response such as Si-based PDs. In this work, delicate optical microcavities are designed to develop a series of bionic PDs with selective response to NIR-I photons, the merits of a narrowband response with a full width at half maximum (FWHM) of <50 nm, and tunability to cover the NIR-I range are highlighted. Inorganic halide perovskite CsPb_0.5Sn_0.5I₃ is chosen as the photoactive layer with comprehensive bandgap and film engineering. As a result, these bionic PDs offer a signal/noise ratio of ≈10⁶, a large bandwidth of 543 kHz and an ultralow detection limit of 0.33 nW. Meanwhile, the peak responsivity (R) and detectivity (D*) reach up to 270 mA W⁻¹ and 5.4 × 10¹⁴ Jones, respectively. Finally, proof-of-concept NIR-I imaging using the PDs is demonstrated to show great promise in real-life application.  相似文献   

    

Kate Higgins  Matthias Lorenz  Maxim Ziatdinov  Rama K. Vasudevan  Anton V. Ievlev  Eric D. Lukosi  Olga S. Ovchinnikova  Sergei V. Kalinin  Mahshid Ahmadi 《Advanced functional materials》2020,30(36)

The instability of hybrid organic–inorganic perovskite (HOIP) devices is one of the significant challenges preventing commercialization. Exploring these phenomena is severely limited by the complexity of the intrinsic electrochemistry of HOIPs, the presence of multiple volatile and mobile ionic species, and the possible role of environmentally induced reactions at surfaces and triple‐phase junctions. Here, in situ studies of the electrochemistry of methylammonium lead bromide perovskite with the Au electrode interface are reported via light‐ and voltage‐dependent time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) imaging of lateral perovskite heterostructures. While ToF‐SIMS allows for the visualization of the chemical composition along the surface and its evolution with light and electrical bias, the interpretation of the multidimensional data obtained is often limited due to strong correlations between chemical signatures and the need to track multiple peaks at once. Here, a machine learning workflow combining the Hough transform and non‐negative matrix factorization and non‐negative tensor decomposition is developed to avoid this limitation and extract salient features of associated chemical changes and to separate the light‐ and voltage‐dependent dynamics. Combining these in situ characterizations and the machine learning workflow provides comprehensive information on the chemical nature of moving species, ion accumulation, and interfacial electrochemical reactions in HOIP devices.  相似文献   

    

Yu‐Hsiang Chang  Chia‐Wei Ku  Yi‐Hua Zhang  Hsiang‐Chen Wang  Jung‐Yao Chen 《Advanced functional materials》2020,30(21)

The exotic photophysical properties of organic–inorganic hybrid perovskite with long exciton lifetimes and small binding energy have appeared as promising front‐runners for next‐generation non‐volatile flash photomemory. However, the long photo‐programming time of photomemory limits its application on light‐fidelity (Li‐Fi), which requires high storage capacity and short programming times. Herein, the spatially addressable perovskite in polystyrene‐block‐poly(ethylene oxide) (PS‐b‐PEO)/perovskite composite film as an photoactive floating gate is demonstrated to elucidate the effect of morphology on the photo‐responsive characteristics of photomemory. The chelation between lead ion and PEO segment promotes the anti‐solvent functionalities of the perovskite/PS‐b‐PEO composite film, thus allowing the solution‐processable poly(3‐hexylthiophene‐2,5‐diyl) (P3HT) to act as the active channel. Through manipulating the interfacial area between perovskite and P3HT, fast photo‐induced charge transfer rate of 0.056 ns^?1, high charge transfer efficiency of 89%, ON/OFF current ratio of 10⁴, and extremely low programming time of 5 ms can be achieved. This solution‐processable and fast photo‐programmable non‐volatile flash photomemory can trigger the practical application on Li‐Fi.  相似文献   

    

Jiaoyi Ning  Yanan Zhu  Zhao Hu  Yuhao Shi  Muhammad Umair Ali  Junpeng He  Yaowu He  Feng Yan  Shihe Yang  Jingsheng Miao  Hong Meng 《Advanced functional materials》2020,30(35)

Ion migration induced interfacial degradation is a detrimental factor for the stability of perovskite solar cells (PSCs) and hence requires special attention to address this issue for the development of efficient PSCs with improved stability. Here, an “S‐shaped, hook‐like” organic small molecule, naphthalene diimide derivative (NDI‐BN), is employed as a cathode interface layer (CIL) to tailor the [6,6]‐phenylC61‐butyric acid methylester (PCBM)/Ag interface in inverted PSCs. By realizing enhanced electron extraction capability via the incorporation of NDI‐BN, a peak power conversion efficiency of 21.32% is achieved. Capacitance–voltage measurements and X‐ray photoelectron spectroscopy analysis confirmed an obvious role of this new organic CIL in successfully blocking ionic diffusion pathways toward the Ag cathode, thereby preventing interfacial degradation and improving device stability. The molecular packing motif of NDI‐BN further unveils its densely packed structure with π–π stacking force which has the ability to effectually hinder ion migration. Furthermore, theoretical calculations reveal that intercalation of decomposed perovskite species into the NDI clusters is considerably more difficult compared with the PCBM counterparts. This substantial contrast between NDI‐BN and PCBM molecules in terms of their structures and packing fashion determines the different tendencies of ion migration and unveils the superior potential of NDI‐BN in curtailing interfacial degradation.  相似文献   

    

Valentin I. E. Queloz  Marine E. F. Bouduban  Ines García‐Benito  Alexander Fedorovskiy  Simonetta Orlandi  Marco Cavazzini  Gianluca Pozzi  Harsh Trivedi  Doru C. Lupascu  David Beljonne  Jaques‐E Moser  Mohammad Khaja Nazeeruddin  Claudio Quarti  Giulia Grancini 《Advanced functional materials》2020,30(28)

2D hybrid perovskites (2DP) are versatile materials, whose electronic and optical properties can be tuned through the nature of the organic cations (even when those are seemingly electronically inert). Here, it is demonstrated that fluorination of the organic ligands yields glassy 2DP materials featuring long‐lived correlated electron–hole pairs. Such states have a marked charge‐transfer character, as revealed by the persistent Stark effect in the form of a second derivative in electroabsorption. Modeling shows that electrostatic effects associated with fluorination, combined with the steric hindrance due to the bulky side groups, drive the formation of spatially dislocated charge pairs with reduced recombination rates. This work enriches and broadens the current knowledge of the photophysics of 2DP, which will hopefully guide synthesis efforts toward novel materials with improved functionalities.  相似文献   

    

Deying Luo  Taoyu Zou  Wengqiang Yang  Beng Xiang  Xiaoyu Yang  Ya Wang  Rui Su  Lichen Zhao  Rui Zhu  Hang Zhou  Thomas P. Russell  Hongyu Yu  Zheng‐Hong Lu 《Advanced functional materials》2020,30(24)

Controlling defects and energy‐band alignments are of paramount importance to the development of high‐performance perovskite‐based photodiodes. Yet, concurrent improvements in interfacial contacts and defect reduction simply by tailoring bottom contacts have not been investigated. An effective strategy is reported that can simultaneously improve energy‐band alignments and structural defects by introducing low‐dimensional contact (LDC) layers at the bottom interface. It is found that LDC‐based perovskites considerably suppress undesirable structural defects induced by microstrains, resulting in reduced nonradiative recombination centers and improved carrier lifetimes. Additionally, the resulting LDC‐based interface structures help block minority carrier injection from the electrodes by forming built‐in electric fields. As a consequence, LDC‐based perovskite photodiodes showed improved light detection capabilities. The result opens an avenue to yield highly efficient photodiodes.  相似文献