Heating‐induced aggregation control for efficient sequential‐cast organic solar cells

Abstract

The aggregation and morphology within the photoactive layer is of considerable significance to boost the power-conversion efficiency (PCE) of organic solar cells (OSCs). Herein, heating-induced aggregation control of nonfullerene acceptor BTP-eC7 during sequential casting was demonstrated. The large aggregates of BTP-eC7 can be significantly reduced by sequential casting of BTP-eC7 hot solution on the D18 fibrillar layer, and further eliminated by sequential casting of BTP-eC7 hot solution on the D18 fibrillar layer heated on hot substrate, leading to stronger faceon π-π stacking and appropriate phase separation within the photoactive layer to promote exciton dissociation and charge transfer. The maximum PCE of D18/BTP-eC7 solar cells can be enhanced from 8.1% of room temperature casting to 15.9% of hot solution, hot-substrate casting, therefore demonstrates that heating-induced aggregation and sequential-casting strategies are a promising approach in improving the performance of OSCs employing nonfullerene acceptors with limited solubility or strong crystallization ability.

A general enlarging shear impulse approach to green printing large-area and efficient organic photovoltaics

“…9 In addition, they also show great application prospects in translucent and wearable applications. [9][10][11][12][13][14][15][16] However, the scalability of active layer films in OSCs prepared by the spin-coating method is poor, resulting in a huge variation in the power conversion efficiency (PCE) between large-area modules and small-area devices. [17][18][19] In addition, harmful halogenated organic solvents such as chlorobenzene (CB) and chloroform (CF) are adopted in most OSCs, which pose a threat to human health and the environment.…”

High‐Efficiency Sequential‐Cast Organic Solar Cells Enabled by Dual Solvent‐Controlled Polymer Aggregation

“…[30][31][32] However, with the recent development of highly crystalline polymer donors and outstanding nonfullerene acceptors, more and more high-performance bilayer devices have been fabricated without relying on orthogonal solvents. [33][34][35][36][37] But the method of using the characteristics of layer-by-layer spin coating to specifically adjust a certain layer to precisely control the morphology and rise the device performance has not been widely studied.…”

Alkoxy-Substituted Quadrupolar Fluorescent Dyes

“…Employing the same procedure as that described in the synthesis of compound 1, product 2 was obtained as a white solid (72 mg, 90%). 1 3. 1,4-Dioxane (5 mL) and H 2 O (5 mL) were mixed and degassed using N 2 .…”

“…Employing the same procedure as that described in the synthesis of compound 1, product 3 was obtained as a white solid (74 mg, 92%). 1 H NMR (500 MHz, CDCl 3 ): δ H 7.70 (d, J = 1.1 Hz, 8H), 6.95 (s, 2H), 3.93 (t, J = 6.4 Hz, 4H), 1.68 (p, J = 6.5 Hz, 4H), 1.37−1.30 (m, 4H), 1.30−1.18 (m, 16H), 0.88 (t, J = 7.1 Hz, 6H). 13 C NMR (125 MHz, CDCl 3 ): δ C 167.…”

“…The remaining solid was dissolved in CH 2 Cl 2 and mixed with Celite545 in preparation for purification by column chromatography (SiO 2 , hexane/CH 2 Cl 2 9:1) to afford product 5 as a yellow solid (995 mg, 85%). 1 (6.04 g, 18.5 mmol) was degassed further using vacuum, followed by a N 2 flow cycle repeated three times and the degassed solvent was injected into this mixture using a cannula. Employing the same procedure as that described in the synthesis of compound 5, product 6 was obtained as a yellow solid (1988 mg, 93%).…”