ORCID Profile
0000-0002-3934-8579
Current Organisation
University of Cambridge
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Publisher: Wiley
Date: 19-12-2022
Abstract: The power conversion efficiency (PCE) of solution‐processed organic–inorganic mixed halide perovskite solar cells has achieved rapid improvement. However, it is imperative to minimize the voltage deficit ( W oc = E g / q − V oc ) for their PCE to approach the theoretical limit. Herein, the strategy of depositing homologous bromide salts on the perovskite surface to achieve a surface and bulk passivation for the fabrication of solar cells with high open‐circuit voltage is reported. Distinct from the conclusions given by previous works, that homologous bromides such as FABr only react with PbI 2 to form a large‐bandgap perovskite layer on top of the original perovskite, this work shows that the bromide also penetrates the perovskite film and passivates the perovskite in the bulk. This is confirmed by the small‐bandgap enlargement observed by absorbance and photoluminescence, and the bromide element ratio increasing in the bulk by time‐of‐flight secondary‐ion mass spectrometry and depth‐resolved X‐ray photoelectron spectroscopy. Furthermore, a clear suppression of non‐radiative recombination is confirmed by a variety of characterization methods. This work provides a simple and universal way to reduce the W oc of single‐junction perovskite solar cells and it will also shed light on developing other high‐performance optoelectronic devices, including perovskite‐based tandems and light‐emitting diodes.
Publisher: Wiley
Date: 03-03-2017
Abstract: Solar cell generates electrical energy from light one via pulling excited carrier away under built-in asymmetry. Doped semiconductor with antireflection layer is general strategy to achieve this including crystalline silicon (c-Si) solar cell. However, loss of extra energy beyond band gap and light reflection in particular wavelength range is known to hinder the efficiency of c-Si cell. Here, it is found that part of short wavelength sunlight can be converted into polarization electrical field, which strengthens asymmetry in organic-c-Si heterojunction solar cell through molecule alignment process. The light harvested by organometal trihalide perovskite nanoparticles (NPs) induces molecular alignment on a conducting polymer, which generates positive electrical surface field. Furthermore, a "field-effect solar cell" is successfully developed and implemented by combining perovskite NPs with organic/c-Si heterojunction associating with light-induced molecule alignment, which achieves an efficiency of 14.3%. In comparison, the device with the analogous structure without perovskite NPs only exhibits an efficiency of 12.7%. This finding provides a novel concept to design solar cell by sacrificing part of sunlight to provide "extra" asymmetrical field continuously as to drive photogenerated carrier toward respective contacts under direct sunlight. Moreover, it also points out a method to combine promising perovskite material with c-Si solar cell.
Publisher: Springer Science and Business Media LLC
Date: 19-10-2020
Publisher: Wiley
Date: 24-04-2015
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Weidong Xu.