Internal Encapsulation for Lead Halide Perovskite Films for Efficient and Very Stable Solar Cells. Issue 19 (28th March 2022)

• Record Type: Journal Article
• Authors: Ge, Yansong; Ye, Feihong; Xiao, Meng; Wang, Haibing; Wang, Chen; Liang, Jiwei; Hu, Xuzhi; Guan, Hongling; Cui, Hongsen; Ke, Weijun; Tao, Chen; Fang, Guojia
• Is Part Of: Advanced energy materials. Volume 12:Issue 19(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-03-28
• Subjects: internal encapsulation -- NbCl 5 -- perovskite solar cells -- stability -- vacancy defects; Energy harvesting -- Materials -- Periodicals; Energy conversion -- Materials -- Periodicals; Energy storage -- Materials -- Periodicals; Photovoltaics -- Periodicals; Fuel cells -- Periodicals; Thermoelectric materials -- Periodicals; 621.31
• DOI: 10.1002/aenm.202200361
• Languages: English
• ISSNs: 1614-6832

Abstract

Abstract: External encapsulation technique as a straightforward craft process has been adopted to prevent the infiltration of moisture and oxygen, thereby improving environmental stabilities of lead halide perovskite solar cells (PSCs). However, irreversible light‐induced degradation originating from various vacancies and ion diffusion or migration inside the device cannot be efficiently solved by external encapsulation. Herein, an internal encapsulation strategy by introducing NbCl5 at the buried tin oxide/perovskite interface and spin‐casting n ‐butylammonium bromide on top of perovskite is developed to comprehensively passivate the vacancies and hence block the channels for ion diffusion or migration. The internal encapsulation strategy results in better homogeneous electron transport layer and effective vacancy passivation at the buried interface and simultaneously generates a more homogeneous, better crystallized perovskite in the vertical direction with significantly reduced residual PbI2 . Furthermore, fewer oxygen vacancies and formation of ultrathin Nb2 O5 lead to a better interfacial energy level alignment for electron transfer. As a result, power conversion efficiency (PCE) of the resulting PSCs is as high as 24.01%. More importantly, the device demonstrates an excellent stability, retaining 88% of its initial PCE at its maximum power point tracking measurement (under 100 mW cm –2 white light illumination at ≈55 °C temperature, in N2 atmosphere) after 1000 h. Abstract : An internal encapsulation strategy is developed to comprehensively passivate vacancy defects inside the device and block the channels for iodide ion diffusion or migration. The internal encapsulation strategy helps to achieve sequential deposited perovskite solar cells with efficiency > 24% as well as excellent stability, with 88% remaining power conversion efficiency compared to the maximum power point tracking measurement after 1000 h.