Asymmetric 3D Hole-Transporting Materials Based on Triphenylethylene for Perovskite Solar Cells

Abstract

Two asymmetric three-dimensional (3D) holetransporting materials (HTMs) containing a triphenylethylene core and peripheral diphenylamine/triphenylamine moieties are first synthesized and successfully used in perovskite solar cells (PSCs). Both HTMs are obtained from facile preparation procedures and simple purification techniques. The X-ray diffraction, aggregation-induced emission properties, absorption and emission spectra, electrochemical properties, thermal stability, density functional theory calculations, hole mobility, scanning electronic microscopy, atomic force microscopy, steady-state and time-resolved photoluminescence, water contact angles, and photovoltaic parameters of the PSCs are compared. The highest power conversion efficiency increases from 12.57% (CJ-02) to 18.56% (CJ-01), rivaling that obtained from the state-of-the-art 2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenylamine)-9,9′-spirobifluorene (spiro-OMeTAD) (18.69%). Further, the lab synthetic cost of CJ-01 is only about 15.5% of the price of commercial spiro-OMeTAD, and the concentration of CJ-01 solution for device fabrication is less than half of the concentration of spiro-OMeTAD solution (30.0 vs 72.3 mg mL −1 ). These results demonstrate that the propeller-shaped compounds with a highly twisted conformation are readily available and promising alternative HTMs for PSCs. Moreover, an applicable strategy to design new HTMs with 3D structure for achieving highly efficient PSCs is proposed.

Bipolar Aggregation-Induced Electrochemiluminescence of Thiophene-Fused Conjugated Microporous Polymers

“…The transient ECL spectra are identical with the photoluminescence spectrum of the ThT-CMP (543 nm) (Figure S8A, curve a), suggesting the identical excited states being generated for both the transient ECL spectrum and photoluminescence spectrum. According to eq (see Experimental Section), the relative ECL efficiencies of the ThT-CMP/S 2 O 8 2– system and the ThT-CMP/TPrA system are measured to be 3.82 and 11.49% with the respect to the standard of the Ru­(bpy) 3 2+ /TPrA system, which is much higher than that of the TBPE-based CMP (TBPE-CMP) (1.72%), polyaniline-[Ru­(bpy) 2 PIC] 2+ (1.0%), and TPE nanocrystals (1.35%) . The lifetime of the ThT-CMP is determined to be 1.23 ns under 405 nm excitation (Figure S8B).…”

Development of Dopant‐Free Organic Hole Transporting Materials for Perovskite Solar Cells

“…The resultant device data of the 4,4′,4″‐(ethene‐1,1,2‐triyl)tris( N,N ‐bis(4‐methoxyphenyl)aniline) (CJ‐01) and 4‐(2‐ethylhexyl)‐2‐(5‐(2‐methylprop‐1‐en‐1‐yl)thiazol‐2‐yl)‐4 H ‐dithieno[3,2‐ b :2′,3′‐ d ]pyrrole (ICTH2) was significant. While CJ‐01‐based devices displayed a PCE of 18.56% in a small active layer, the PCE of ICTH2 HTM was 18.75% with a working area of 2.18 cm 2 …”

“…On the other hand, there are few asymmetric shapes of undoped HTMs reported. [79,80] Organic dye derivatives have been intensively applied for the development of cost-effective and printable solar cells. A few undoped HTM-based organic dyes for PSCs, such as anthanthrone (ANT), [63,65] quinacridone (QA), [64] and carbazole, [81] [82] A robust PSC with 18.3% efficiency with 91% retention after 30 days without encapsulation under 50-75% relative humidity without dopants was shown.…”

Advancements in organic small molecule hole-transporting materials for perovskite solar cells: past and future

“…317 Many metastable cavities are formed by twisted conformations and hydrogen bonds, which can help with hole transport. 318 A group of new Vshaped hole-transporting materials containing TPD-type moieties conjoined by a Trogers base core was formed by Braukyla et al The TB center provides angle-wise orientation for TPD fragments, preventing crystallization and making the examined compound completely amorphous, whereas directed parasubstituted TPD type moieties have high charge mobility. These TB-based HTMs are amorphous, don't need to be annealed at elevated temperatures, and can be treated in the air.…”