A Review of Inorganic Hole Transport Materials for Perovskite Solar Cells

Abstract

IntroductionIn recent decades, the world has come to a consensus that new green energy sources are vital for sustainable development. Solar energy has been regarded as an alternative source of energy supply. Photovoltaic (PV) technology has progressed for decades with massive efforts devoted. Alternative technologies for photon to electron power conversion include, for instance, This review presents various hole transport layers (HTLs) employed in perovskite solar cells (PSCs) in pursuing high power conversion efficiency (PCE) and functional stability. The PSCs have achieved high PCE (over 23%, certified by NREL) and more efforts have been devoted into research for stability enhancement. Inorganic HTLs become a popular choice as selective contact materials because of their intrinsic chemical stability and low cost. HTLs and electron transport layers (ETLs) are critical components of PSCs due to the requirement to create charge collection selectivity. Herein the authors provide an overview on inorganic HTLs synthesis, properties, and their application in various PSCs for both mesoporous and planar architectures. InorganicHTLs with appropriate properties, such as proper energy level and high carrier mobility, can not only assist with charge transport, but also improve the stability of PSCs under ambient conditions. The importance of interfacial chemistry and interfacial charge transport is further addressed to understand the underlying mechanism of related degradation and carrier dynamic. It is expected that the success of the inorganic HTL in PSCs can stimulate further research and bring real impact for future photovoltaic technologies.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/admi.201800882. super-mesostructure Al 2 O 3 scaffold, achieving a PCE above 9% [6] and 10%, [7] respectively.

A monolithic nanostructured-perovskite/silicon tandem solar cell: feasibility of light management through geometry and materials selection

“…But even at these values, the produced optical losses would be still a 32% lower than the ones of the planar cell. According to a recent review, most of the HTL materials incorporated in high efficiency perovskite cells have low refractive www.nature.com/scientificreports www.nature.com/scientificreports/ indices, under 2 in the visible region 42 . This means that the vast majority of materials can offer losses lower than 8 mA/cm 2 in our model.…”

The use of nickel oxide as a hole transport material in perovskite solar cell configuration: Achieving a high performance and stable device

“…flows through. 6,[51][52][53][54][55] Besides, nickel oxide can be synthesized via several methods, including the chemical deposition method, 56,57 solution growth technique, 58 SILAR method, 59 thermal decomposition, combustion method, 60 sonochemical, electrolysis, 61 solid-state reaction, 62 chemical precipitation and chemical combustion methods, 51 pulsed laser deposition 52 amongst others. 53,54 Before delving into the details of our present review, it is important to mention several interesting works on NiO, which relates to its application as HTM.…”

“…The article discussed the synthesis, properties, interfacial mechanisms, and probable applications in planar and mesoporous architectures. 55 Zhuang et al fabricated perovskite light-emitting diodes using NiO material synthesized by magnetron sputtering as HTM. The effects of sputtering power, pressure and argon to oxygen ratio on the electrical, structural, optical, and morphological properties of the NiO materials were studied.…”

Modification of NiOx hole transport layers with 4-bromobenzylphosphonic acid and its influence on the performance of lead halide perovskite solar cells

“…The diminishing gap between the performance of both device architectures has been majorly possible due to optimizing the inorganic hole transport layers (HTLs). In particular, nickel oxide (NiO x ) films proved to be promising, as they allow facile processing, good stability and efficient hole extraction [8,9]. Furthermore, different doping procedures for NiO x such as incorporation of copper, cesium or silver ions have led to improved device performance and are opening up pathways for further optimisations [10][11][12].…”