A Bithiazole‐Substituted Donor for High‐Efficiency Thick Ternary Organic Solar Cells via Regulation of Crystallinity and Miscibility

Abstract

Organic solar cells (OSCs) with thick active layers exhibit great potential for future roll‐to‐roll mass production. However, increasing the thickness of the active layer generally leads to unfavorable morphology, which decreases the device's performance. Therefore, it is a critical challenge to achieve OSCs with high efficiency and thick film simultaneously. Herein, a small molecular donor, ZW1, incorporating a bithiazole unit along with a thiophene group as a π‐bridge is reported. ZW1 with high crystallinity is employed to fabricate D18:ZW1:Y6 ternary devices, which enhances the crystallization, optimizes the morphology, and suppresses bimolecular recombination. Additionally, ZW1 shows better miscibility with D18, resulting in the preferred vertical phase distribution. As a result, an outstanding power conversion efficiency (PCE) of 18.50% is realized in ternary OSCs with 120 nm active layer thickness. Importantly, the thick ternary OSCs attain a high PCE of 16.67% (thickness ≈300 nm), significantly higher than the corresponding binary devices (13.50%). The PCE of 16.67% is one of the highest values for thick‐film OSCs reported to date. This work demonstrates that the incorporation of highly crystalline small‐molecule donors into ternary OSCs, possessing good miscibility with host materials, presents an effective strategy for fabricating highly efficient thick OSCs.

Reducing the Open-Circuit Voltage Loss of PbS Quantum Dot Solar Cells via Hybrid Ligand Exchange Treatment

“…The plot slope of the hybrid HTL devices (1.12kT/ q) is significantly lower than that of the control group QD devices (1.47kT/q), indicating a substantial reduction in trapassisted recombination. 45 This will contribute to the enhancement of V OC . The electrochemical impedance spectroscopy (EIS) tests under dark conditions are presented in Figure 4b as Nyquist plots, and they are fitted by using an equivalent circuit (illustrated in the inset of Figure 4b).…”

“…We studied the light intensity dependence of V OC using the following relation: , where n is the diode ideality factor, k is the Boltzmann constant, T is the temperature in Kelvin, q is the elementary charge, and C is a fitting parameter collecting all the terms independent of light intensity. The plot slope of the hybrid HTL devices (1.12 kT / q ) is significantly lower than that of the control group QD devices (1.47 kT / q ), indicating a substantial reduction in trap-assisted recombination . This will contribute to the enhancement of V OC .…”

Efficiency enhancement of dopant-free perovskite solar cells by employing fluoro-substituted electron donor–electron acceptor type polymeric hole-transporting materials

“…Organic-inorganic metal halide-based perovskite solar cells (PVSCs) have become one of the fastest growing photovoltaic technologies in the past few decades. 1,2 The power conversion efficiency (PCE) has risen up to over 25%. 3 The rapid development is attributed to the excellent photo-electric properties of perovskite and other functional materials.…”

Regulating the reorganization energy and crystal packing of small-molecule donors enables the high performance of binary all-small-molecule organic solar cells with a slow film growth rate

“…Bulk heterojunction organic solar cells (OSCs) are attracting significant attention due to their ability to convert optical energy into electricity, while being light weight, mechanically flexible, and semi-transparent, among other advantages. [1][2][3][4][5][6][7][8][9][10][11] Typically, the OSCs are principally composed of a P-type organic semiconductor as the donor and an N-type organic semiconductor as the acceptor. The OSCs can be divided into two categories, polymer OSCs and all-small-molecule OSCs (ASM-OSCs), based on their constituent materials.…”