Dopant‐Free Hole Transporting Polymers for High Efficiency, Environmentally Stable Perovskite Solar Cells

Abstract

Over the past fi ve years, a rapid progress in organometal-halide perovskite solar cells has greatly infl uenced emerging solar energy science and technology. In perovksite solar cells, the overlying hole transporting material (HTM) is critical for achieving high power conversion effi ciencies (PCEs) and for protecting the air-sensitive perovskite active layer. This study reports the synthesis and implementation of a new polymeric HTM series based on semiconducting 4,8-dithien-2-yl-benzo[1,2-d ;4,5-d ′]bistriazolealt -benzo[1,2-b :4,5b ′]dithiophenes (pBBTa-BDTs), yielding high PCEs and environmentally-stable perovskite cells. These intrinsic (dopant-free) HTMs achieve a stabilized PCE of 12.3% in simple planar heterojunction cells-the highest value to date for a polymeric intrinsic HTM. This high performance is attributed to effi cient hole extraction/collection (the most effi cient pBBTa-BDT is highly ordered and orients π-face-down on the perovskite surface) and balanced electron/ hole transport. The smooth, conformal polymer coatings suppress aerobic perovskite fi lm degradation, signifi cantly enhancing the solar cell 85 °C/65% RH PCE stability versus typical molecular HTMs.

The Effect of Dopant‐Free Hole‐Transport Polymers on Charge Generation and Recombination in Cesium–Bismuth–Iodide Solar Cells

“…It has been suggested that dopant-free HTMs are advantageous for device stability,a st he dopantsc an be involved in degradation reactions. [35][36][37] In this report, we comparet he dopant-free polymer HTMs poly[[2,3-bis(3-octyloxyphenyl)-5,8-quinoxalinediyl]-2,5-thiophenediyl] (TQ1),p oly[N,N'-bis(2-hexyldecyl)isoindigo-6,6'-diyl-alt-3,3''-dioctyl-2,2',5',2''-terthiophene-5,5''-diyl] (P3TI), and P3HT for use in CsBi 3 I 10 -based solar cells. [35][36][37] In this report, we comparet he dopant-free polymer HTMs poly[[2,3-bis(3-octyloxyphenyl)-5,8-quinoxalinediyl]-2,5-thiophenediyl] (TQ1),p oly[N,N'-bis(2-hexyldecyl)isoindigo-6,6'-diyl-alt-3,3''-dioctyl-2,2',5',2''-terthiophene-5,5''-diyl] (P3TI), and P3HT for use in CsBi 3 I 10 -based solar cells.…”

Non‐Conjugated Polymer as an Efficient Dopant‐Free Hole‐Transporting Material for Perovskite Solar Cells

“…Aw ell-known strategy to design dopant-free HTMs for PSCs is building donor-acceptor (D-A) conjugated small molecular or polymer HTMs with enhanced intermolecular packing and improved charge-transporting properties. [26][27][28][29][30] Nevertheless, most D-A dopant-free HTMs stillr equire uneconomical raw materials, multi-step synthesis routes, and/or complicated purificationp rocedures. Additionally,D -A conjugated polymer dopant-free HTMs with rigid conjugated backbones are usually difficult to process into good thin films owing to solubility problems.…”

Stitching triple cation perovskite by a mixed anti-solvent process for high performance perovskite solar cells

“…[3][4][5][6][7][8][9][10][11][12] In order to make it more conducive to practical application, the degradation mechanism of perovskite in air and the fabrication process of larger sized devices are investigated by a lot of research groups. [13][14][15][16][17] As a result, precisely controlling the growth of perovskite crystals has also become an interesting topic to explore the fundamental properties and growth dynamics of high quality perovskite films for efficient solar cells.…”