Cyclopentadiene‐Based Hole‐Transport Material for Cost‐Reduced Stabilized Perovskite Solar Cells with Power Conversion Efficiencies Over 23%

Abstract

Hole transport materials (HTM) are an important component in perovskite solar cells (PSC). Despite a multitude of HTMs developed in recent years, only few of them lead to solar cells with efficiencies over 20%. Therefore, it is still a challenge to develop high‐performing HTMs, which have ideal energy levels of the frontier orbitals, are highly efficient in transporting charges, and stabilize the solar cell at the same time. In this work, the development of a structurally novel molecular HTM, CPDA 1, is described which is based on a common cyclopentadiene core and can be efficiently and inexpensively synthesized from readily available starting materials, which is important for future realization of low‐cost photovoltaics on larger scale. Due to excellent optoelectronic, thermal, and transport properties, CPDA 1 not only meets the envisioned properties by reaching high efficiencies of 23.1%, which is among the highest reported to date, but also contributes to a respectable long‐term stability of the PSCs.

A Trifluoroethoxyl Functionalized Spiro‐Based Hole‐Transporting Material for Highly Efficient and Stable Perovskite Solar Cells

“…Therefore, the HOMO level became deeper in Spiro-4TFETAD, which benefits to achieve higher V OC and thereby favored the high-effciency PSCs. [38] Another essential prerequisite of HTMs is charge transport. First, the hole mobility (μ h ) was determined by a spacecharge-limited current (SCLC) method to investigate the charge-transport property of trifluoroethoxyl functionalization in HTM molecules.…”

“…Therefore, the HOMO level became deeper in Spiro‐4TFETAD, which benefits to achieve higher V OC and thereby favored the high‐effciency PSCs. [ 38 ]…”

Bifunctional Passivation through Fluoride Treatment for Highly Efficient and Stable Perovskite Solar Cells

“…[ 4–6 ] Among them, mesoporous structure‐based PSCs have achieved high efficiency and attracted much attention. [ 7,8 ] In the mesoporous structure, the mesoporous titanium oxide (m‐TiO 2 ) electron transport layer (ETL) contributes to PSC efficiency and stability by providing charge transport channels. [ 9,10 ] Two major factors contribute to the high performance of m‐TiO 2 ‐based PSCs.…”

“…[4][5][6] Among them, mesoporous structure-based PSCs have achieved high efficiency and attracted much attention. [7,8] In the mesoporous structure, the mesoporous titanium oxide (m-TiO 2 ) electron transport layer (ETL) contributes to PSC efficiency and stability resulting in charge recombination and moisture permeation. [17,18] This is an important factor that contributes to a low open circuit voltage, hysteresis, and device instability.…”

Improving the Stability and Efficiency of Perovskite Solar Cells by a Bidentate Anilinium Salt

“…Also, there is an explicit concern about the PSC production under sustainable and cost-effective conditions. − An approach to reach these goals is the replacement of the toxic halogenated solvents used as antisolvent to prepare perovskite film. Among the strategies, we highlight the development of gas quenching methods, − which triggers the perovskite crystallization by blowing an inert gas on the film.…”