A Dual-Functional Conjugated Polymer as an Efficient Hole-Transporting Layer for High-Performance Inverted Perovskite Solar Cells

Abstract

Conductive polyelectrolytes such as P3CT-Na have been widely used as efficient hole-transporting layers (HTLs) in inverted perovskite solar cells (PSCs) due to their high hole mobility. However, the acid−base neutralization reaction is indispensable for preparing such polyelectrolytes and the varied content of cations usually leads to poor reproducibility of the device performance in PSCs. In this work, a commercially available polymer poly[3-(4-carboxybutyl)thiophene-2,5-diyl] (P3CT) was directly applied as an HTL in PSCs for the first time. Encouragingly, it was found that due to the dual functionality of carboxyl groups on side chains, a thin layer of P3CT can not only strongly anchor on ITO electrode and optimize its work function but also show an effective passivation effect toward perovskite active layer. Benefiting from such dual functionality, a uniform perovskite film with better quality was obtained on P3CT. As a result, the P3CT-based PSCs show much lower nonradiative recombination and achieve a champion power conversion efficiency (PCE) of 21.33% with a high fill factor (FF) of 83.6%. Impressively, as the device area is increased to 0.80 cm 2 , a PCE of 19.65% can still be obtained for the PSCs based on P3CT HTL. Our work provides important strategy for developing HTLs for high-performance PSCs.

Configurable Organic Charge Carriers toward Stable Perovskite Photovoltaics

“…Passivation, however, can not only be achieved through the introduction of fluorine atoms. The incorporation of terminal anchoring groups such as carboxylic and cyano-based units also serves as an effective strategy to passivate the perovskite film . This is primarily achieved through these polar functional groups’ Lewis base characteristic to form a coordination interaction with Pb 2+ ion defects .…”

High efficiency (>20%) and stable inverted perovskite solar cells: current progress and future challenges

“…Various organic molecules have been used to treat the perovskite surface at the ETL and HTL interfaces to achieve high-quality defect-free perovskite films. In this context, the stability of the champion devices was maintained by using organic molecules/slats such as the 2FBT2FPDI (bisfluorobenzothiadiazole-dithiophene-fused bis- N , N ′-bis(1-ethylpentyl)-perylene-3,4,9,10-tetracarboxylic acid bisimides), 54 CIGD-PCBM (modified PCBM), 55 benzenebutanammonium iodide (PBAI), 41 spiro[fluorene-9,9-phenanthren-10-one] derivative (MS-OC), 56 2,8-bis(4-(bis(4-methoxyphenyl)amino)phenyl)-5-dodecyl-4 H thieno[2′,3′:4,5] thieno[3,2- c ]thieno[2′,3′:4,5]thieno[2,3- e ]azepine-4,6(5 H )-dione (MPA-BTTI), 57 poly[3-(4-carboxybutyl)thiophene-2,5-diyl] (P3CT) 58 PFDT-COOH and PFDT-COOH and fluorinated derivative, PFDT-2F-COOH, 59 2-phenylethylammonium iodide (PEAI), 15 pyridine-based polymers (PPY2), 60 piperazinium iodide (PI), 42 2,2′-bithiazolothienyl-4,4′,10,10′-tetracarboxydiimide (PDTzTI), 61 surface-anchoring alkylamine ligands (AALs), 22 S -acetylthiocholine chloride, 62 tetraoctylammonium bromide, 47 5-methoxy-2-mercaptobenzimidazole (MBI-OCH 3 ), 34 buffer layer containing C 60 :Co-TiO 2 , 63 surface passivation poly(styrene- co -acrylonitrile) polymer (PS-PAN polymer), 32 p-conjugated dual-ligand 1,4-phenylmercaptan (PHMT), 30 and Cd x Zn 1− x Se y S 1− y quantum dots (QDs). 64…”

Polymers in High-Efficiency Solar Cells: The Latest Reports

“…To eliminate recombination defects, the Lewis base character of the −COOH group could efficiently passivate the under-coordinated Pb 2+ ions at the HTL/perovskite interface. As a consequence of using the P3CT as HTL, a significant PCE of 21.09% was successfully produced [ 161 ].…”