Defect Passivation by a D–A–D Type Hole-Transporting Interfacial Layer for Efficient and Stable Perovskite Solar Cells

Abstract

In this work, we present a series of donor–acceptor–donor type of small molecules (BDAD, ODAD, and DDAD) based on the triphenylamine (TPA) and dithienopyrrolobenzothiadiazole (DTPBT) units, which are distinguished by alkyl chains of different lengths grafted on the DTPBT unit, as a hole-transporting interfacial layer for perovskite solar cells (PSCs). The incorporation of the DTPBT units is beneficial for not only carrier transportation but also potential defects passivation via Pb–N/S interactions. A champion power conversion efficiency (PCE) of 22.76% has been achieved on PSCs based on BDAD with the n-butyl side chains. Those devices without encapsulation retain over 96% of their initial PCE for more than 120 days. The improved stability is attributed to the restraint of the generation of δ-phase perovskite as supported by the grazing incidence wide-angle X-ray scattering analyses.

Fluorene-Modified Zinc Porphyrin as Low-Cost Hole-Transporting Material for Efficient Perovskite Solar Cells

“…The result of GIWAXS further indicates that the coverage of a spin-coated layer of ZnP-FL did not change the crystal structure of the PVK (Figure S5). 27 We fabricated typical planar n-i-p PSCs to explore the performance of ZnP-FL as a HTM. The cross-sectional view of the device is shown in Figure S6, with a structure of ITO/ SnO 2 /FA x MA 1-x PbI 3 /HTM/Au.…”

Dicyclopentadithienothiophene (DCDTT)-based organic semiconductor assisted grain boundary passivation for highly efficient and stable perovskite solar cells

“…The development of organic small molecular passivation agents has become an important topic worldwide because they are benecial for not only carrier transportation, but also simultaneously passivating multiple surface defects of perovskites to further increase the photovoltaic performance of PSCs. [69][70][71] In this connection some organic molecules such as SY2, SY4, 72 SGT-421, and SGT-422, 73 as shown in Fig. S1b, † have been reported as donor passivation agents for the fabrication of PSCs exhibiting a PCE of 18.96%, 18.44% 17.27%, and 10.01%, respectively.…”

Indolocarbazole-core linked triphenylamine as an interfacial passivation layer for perovskite solar cells

“…To passivate the surface defects of perovskite films, we herein design and synthesize two novel P-type organic molecules 19–22 through the combination of indolocarbazole and triphenylamine: 4,4′-(5,11-dioctyl-5,11-dihydroindolo[3,2- b ]carbazole-6,12-diyl)bis( N , N -bis(4-methoxyphenyl)aniline) ( TM5 ) and 4,4′-(5,11-dioctyl-5,11-dihydroindolo[3,2- b ]carbazole-6,12-diyl)bis( N , N -bis(4-(methylthio)phenyl)aniline) ( TM6 ) to coat onto the perovskite surface. The structures of TM5 and TM6 are shown in Scheme 1.…”

“…To passivate the surface defects of perovskite lms, we herein design and synthesize two novel P-type organic molecules [19][20][21][22] through the combination of indolocarbazole and triphenylamine:…”

“…The indolocarbazole has a large p conjugation plane and high electron cloud density, which is benecial to hole transport and defect passivation. 20,23 In addition, as triphenylamine has a suitable ionization potential and highest occupied molecular orbital (HOMO) energy level, the formed TM5 and TM6 molecules based on the combination of triphenylamine with indolocarbazole may possess energy levels well matching those of perovskite. 24,25 The difference of TM5 and TM6 is the substituents on the triphenylamine unit; the former has a methoxy group and the latter has a methylthio group.…”