宽光谱高比探测率有机光电探测器

High Detectivity and Broadband Organic Photodetectors

为实现有机光电探测器对三基色(红、绿、蓝)的全响应以及器件性能的改善,研究了在聚(3-己基噻吩)(P3HT)∶[6,6]-苯基-C61-丁酸甲酯(PC61BM)活性层中,掺入窄带隙材料(4,8-双-(2-乙基己氧基)-苯并[1,2-b:4,5-b′]二噻吩)-(4-氟代噻并[3,4-b]噻吩)(PBDT-TT-F)实现光谱拓宽以及通过提高阳极修饰层电子注入势垒来降低暗电流,改善探测器性能的方法,研究了PBDT-TT-F掺杂浓度以及修饰层厚度对探测器光电学性能的影响规律.在此基础上,获得了一个覆盖400~750nm波长范围的探测器,并且在低偏压-1V下三基色的线性动态范围和比探测率分别达到了81、80、81dB和2.7×1012、2.0×1012、2.6×1012 Jones.结果表明:在保持原有二相体异质结薄膜的微观形貌和电学特性前提下,掺入13wt.%少量光谱拓宽材料可实现活性层的光谱拓宽.采用合适厚度的三氧化钼(MoO3)层替换原有的聚乙撑二氧噻吩-聚(苯乙烯磺酸盐)(PEDOT∶PSS)阳极修饰层,可使探测器的三基色线性动态范围和比探测率大幅提高.该研究为研发宽光谱高探测率三基色有机光电探测器提供了一种新思路.

In order to achieve the full response of three primary colors(red,green,blue)of organic photodetectors and the improvement of devices performances,the spectral broadening of organic active layer based on tri-phase bulk heterojunction formed by Poly(3-hexylthiophene)(P3HT)∶[6,6]-Phenyl-C 61-butyric acid methyl ester(PC 61 BM)doped with narrow band material poly-{[4,8-bis[(2-ethylhexyl)oxy]-benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl]-alt-[3-fluore-2-(octyloxy)cabonyl-thieno[3,4-b]thiophene-4,6-diyl]}(PBDT-TT-F)was investigated.Additionally,the dark current was reduced due to the increase of electron injection barrier by the replacement of anode buffer layer so as to improve the devices performances.The influence of PBDT-TT-F doping concentration and buffer layer thicknesses on devices optoelectronic performances was discussed systemly.On this basis,the photodetectors with 400~750 nm wide spectra was obtained.At-1 V bias,the linear dynamic range and the detectivity reached 81,80,81 dB and 2.7×10^12,2.0×10^12,2.6×10^12 Jones respectively under illumination of three primary colors.The results show that the absorption spectra of the active layer can be broadened by adding a small amount of spectral broadening material under the premise of maintaining the morphology and electrical properties of the original binary bulk heterojunction.Utilizing Molybdenum trioxide(MoO 3)with optimized thickness to replace original Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)dry re-dispersiblepellets](PEDOT∶PSS)anode buffer layer so as to further improve the performance.Hence,the linear dynamic range and the detectivity of the devices were enhanced obviously.The present study paves the way for high detectivity and broadband organic photodetectors based on tri-phase bulk heterojunction.