Wolansky Jakob, Hoffmann Cedric, Panhans Michel, Winkler Louis Conrad, Talnack Felix, Hutsch Sebastian, Zhang Huotian, Kirch Anton, Yallum Kaila M, Friedrich Hannes, Kublitski Jonas, Gao Feng, Spoltore Donato, Mannsfeld Stefan C B, Ortmann Frank, Banerji Natalie, Leo Karl, Benduhn Johannes
Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Institute of Applied Physics, Technische Universität Dresden, Nöthnitzer Str. 61, 01187, Dresden, Germany.
Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, Bern, 3012, Switzerland.
Adv Mater. 2024 Dec;36(50):e2402834. doi: 10.1002/adma.202402834. Epub 2024 Nov 6.
Typically, organic solar cells (OSCs) and photodetectors (OPDs) comprise an electron donating and accepting material to facilitate efficient charge carrier generation. This approach has proven successful in achieving high-performance devices but has several drawbacks for upscaling and stability. This study presents a fully vacuum-deposited single-component OPD, employing the neat oligothiophene derivative DCV2-5T in the photoactive layer. Free charge carriers are generated with an internal quantum efficiency of 20 % at zero bias. By optimizing the device structure, a very low dark current of 3.4 · 10A cm at -0.1 V is achieved, comparable to the dark current of state-of-the-art bulk heterojunction OPDs. This optimization results in specific detectivities of 1· 10Jones (based on noise measurements), accompanied by a fast photoresponse (f = 200 kHz) and a broad linear dynamic range (> 150 dB). Ultrafast transient absorption spectroscopy unveils that charge carriers are already formed at very short time scales (< 1 ps). The surprisingly efficient bulk charge generation mechanism is attributed to a strong electronic coupling of the molecular exciton and charge transfer states. This work demonstrates the very high performance of single-component OPDs and proves that this novel device design is a successful strategy for highly efficient, morphological stable and easily manufacturable devices.
通常，有机太阳能电池（OSCs）和光电探测器（OPDs）由供体和受体材料组成，以促进高效电荷载流子的产生。这种方法已被证明在实现高性能器件方面是成功的，但在扩大规模和稳定性方面存在一些缺点。本研究展示了一种完全真空沉积的单组分OPD，在光活性层中采用纯寡聚噻吩衍生物DCV2-5T。在零偏压下，自由电荷载流子的内部量子效率为20%。通过优化器件结构，在-0.1 V时实现了3.4·10A cm的极低暗电流，与最先进的体异质结OPD的暗电流相当。这种优化导致特定探测率达到1·10Jones（基于噪声测量），同时具有快速光响应（f = 200 kHz）和宽线性动态范围（> 150 dB）。超快瞬态吸收光谱表明，电荷载流子在非常短的时间尺度（< 1 ps）内就已形成。这种惊人的高效体电荷产生机制归因于分子激子与电荷转移态之间的强电子耦合。这项工作展示了单组分OPD的非常高性能，并证明这种新颖的器件设计是实现高效、形态稳定且易于制造的器件的成功策略。
