Rational Design of Dopant‐Free Coplanar D‐π‐D Hole‐Transporting Materials for High‐Performance Perovskite Solar Cells with Fill Factor Exceeding 80%. Issue 39 (7th August 2019)

• Record Type: Journal Article
• Authors: Chen, Yatong; Xu, Xiuwen; Cai, Ning; Qian, Sainan; Luo, Ruixi; Huo, Yanping; Tsang, Sai‐Wing
• Is Part Of: Advanced energy materials. Volume 9:Issue 39(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-08-07
• Subjects: dopant free -- hole mobility -- hole‐transporting materials -- molecular packing -- perovskite solar cells; Energy harvesting -- Materials -- Periodicals; Energy conversion -- Materials -- Periodicals; Energy storage -- Materials -- Periodicals; Photovoltaics -- Periodicals; Fuel cells -- Periodicals; Thermoelectric materials -- Periodicals; 621.31
• DOI: 10.1002/aenm.201901268
• Languages: English
• ISSNs: 1614-6832

Abstract

Abstract: In this paper, two novel D‐π‐D hole‐transporting materials (HTM) are reported, abbreviated as BDT‐PTZ and BDT‐POZ, which consist of 4, 8‐di(hexylthio)‐benzo[1, 2‐ b :4, 5‐ b ′]dithiophene (BDT) as π‐conjugated linker, and N ‐(6‐bromohexyl) phenothiazine (PTZ)/ N ‐(6‐bromohexyl) phenoxazine (POZ) as donor units. The above two HTMs are deployed in p‐i‐n perovskite solar cells (PSCs) as dopant‐free HT layers, exhibiting excellent power conversion efficiencies of 18.26% and 19.16%, respectively. Particularly, BDT‐POZ demonstrates a superior fill factor of 81.7%, which is consistent with its more efficient hole extraction and transport verified via steady‐state/transient fluorescence spectra and space‐charge‐limited current technique. Single‐crystal X‐ray diffraction characterization implies these two molecules present diverse packing tendencies, which may account for various interfacial hole‐transport ability in PSCs. Abstract : With the synthesis of two novel hole transport materials, the inverted planar perovskite solar cell achieves a high fill factor of 81.7%, with an efficiency exceeding 19%. More importantly, a highly possible correlation between the molecular packing, hole mobility, and device performance is revealed, which provides some insights for the rational design of hole transport materials.