The State‐of‐the‐Art Solution‐Processed Single Component Organic Photodetectors Achieved by Strong Quenching of Intermolecular Emissive State and High Quadrupole Moment in Non‐Fullerene Acceptors

Abstract

A bulk‐heterojunction (BHJ) blend is commonly used as the photoactive layer in organic photodetectors (OPDs) to utilize the donor (D)/acceptor (A) interfacial energetic offset for exciton dissociation. However, this strategy often complicates optimization procedures, raising serious concerns over device processability, reproducibility and stability. Herein, we demonstrate highly efficient OPDs fabricated with single‐component organic semiconductors via solution‐processing. The non‐fullerene acceptors (NFAs) with strong intrinsic D/A character are used as the photoactive layer, where the emissive intermolecular charge transfer excitonic (CTE) states are formed within <1 ps, and efficient photocurrent generation is achieved via strong quenching of these CTE states by reverse bias. Y6 and IT‐4F based OPDs show excellent OPD performances; low dark current density (∼10−9 A cm−2), high responsivity (≥ 0.15 A W−1), high specific detectivity (> 1012 Jones) and fast photo‐response time (< 10 µs), comparable to the state‐of‐the‐art BHJ OPDs. Together with strong CTE state quenching by electric field, these excellent OPD performances are also attributed to the high quadrupole moments of NFA molecules, which can lead to large interfacial energetic offset for efficient CTE dissociation. Our work opens a new way to realize efficient OPDs using single‐component systems via solution‐processing and provides important molecular design rules.This article is protected by copyright. All rights reserved

New Avenues for Organic Solar Cells Using Intrinsically Charge-Generating Materials

“…An exciting variant of this idea would be to employ a wide bandgap material capable of singlet fission, followed by triplet injection into Y6, to provide triplet excitons that might dissociate under the influence of the interfacial field. Finally, we also note that EP junctions may be particularly suitable for organic photodetectors, where the energy level differences and bilayer architecture would be expected to lead to low dark current–a key figure of merit for photodetectors …”

“…Finally, we also note that EP junctions may be particularly suitable for organic photodetectors, where the energy level differences and bilayer architecture would be expected to lead to low dark current–a key figure of merit for photodetectors. 64 …”

Halogenation Strategy of Thiophene Derived Solvent Additives Enables Optimized Morphology for Organic Solar Cells with 19.17% Efficiency

“…Organic solar cells (OSCs) featuring a bulkheterojunction (BHJ) active layer, which comprises polymer donors (PDs) and nonfullerene small-molecule acceptors (SMAs), have garnered significant attention, mainly due to their unique potential applications in light-to-power generators and flexible electronics using the rapid-printing and largearea-fabrication techniques. [1,2,3,4,5,6,7,8,9] Over the past four years, the evolution of the banana-shaped Y-series SMAs (Y-SMAs), marked by near-infrared (NIR) absorption, strong extinction coefficient, and low energy loss (E loss ), [10,11,12] has paved the way for ground-breaking power conversion efficiencies (PCEs) exceeding 19% in the state-of-the-art OSCs. [7,[13][14][15][16][17][18][19][20] While the judicious molecular design of active layer materials is instrumental, [21][22][23][24][25][26] the finelyoptimized active layer morphology with a bi-continuous and nanoscale interpenetrating network fiber structure also plays a crucial role in enhancing the PCEs of OSCs.…”