Work

Interfacial positioning of LiI-doped PEDOT:PSS in homojunction bilayer towards hole extraction and perovskite growth for solar cells

Year: 2025

Type: article

Abstract: Organic semiconductors have been widely explored with additive and interface engineering to find their novel properties and applications for solid-state devices. In this work, conductive polymer PEDOT:PSS was doped with lithium iodide (LiI) via solution processing to induce the PEDOT separation from PSS phase and PEDOT linear conformation. With this restructuring, LiI-doped PEDOT:PSS film exhibits a higher electrical conductivity and lower work function, and its surface becomes smoother and less hydrophilic. Herein, we developed a homojunction bilayer by stacking LiI-doped PEDOT:PSS and pristine PEDOT:PSS via spin-coating and annealing processes, and elucidated an interfacial coupling strategy via inter-PEDOT crystallization to tailor the textural coherence and electrical enhancement of the compatible bilayer. This bilayer surface benefits the growth of superior perovskite (MAPbI 3 ) film under ambient medium-humidity and low-oxygen conditions, and offers an excellent capability for the hole extraction from adjacent perovskite. A dependence of the carrier dynamics on the perovskite crystallinity and PEDOT:PSS conductivity is suggested. In a simple inverted perovskite solar cell (PSC) without encapsulation, the homojunction bilayer facilitates charge-carrier separation and suppresses recombination to promote photocurrent with negligible hysteresis, attaining a marked enhancement by 22.8 % in the power conversion efficiency surpassing the pristine single-layer. This study paves the way for a full exploration of the PEDOT:PSS morphology and conductivity in the transport bilayer design towards further advancement of optoelectronic devices. • LiI doping in PEDOT:PSS film favors electrical conductivity and smooth surface. • Interfacial coupling strategy tailors textural coherence and electrical enhancement. • Compatible PEDOT:PSS bilayer benefits perovskite growth and rapid hole extraction. • Homojunction bilayer promotes charge collection and photocurrent yield.

Source: Results in Surfaces and Interfaces

DOI: 10.1016/j.rsurfi.2025.100506

Authors: Chien-Tsung Wang, Kuo-Sheng Chung

Institution: National Yunlin University of Science and Technology

Language: English

Topic: Perovskite Materials and Applications

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

SDG: Affordable and clean energy

Open Access status: gold

Estimated APC paid: $1,190