光子学报  2019, Vol. 48 Issue (10): 1004001  DOI: 10.3788/gzxb20194810.1004001 0

### 引用本文

AN Tao, WANG Yong-qiang, ZHANG Jun. Achieving High-detection Organic Photodetectors Covering the Visible Range by Using a Ternary Active Layer[J]. Acta Photonica Sinica, 2019, 48(10): 1004001. DOI: 10.3788/gzxb20194810.1004001.

### 文章历史

(西安理工大学 自动化与信息工程学院, 西安 710048)

Achieving High-detection Organic Photodetectors Covering the Visible Range by Using a Ternary Active Layer
AN Tao , WANG Yong-qiang , ZHANG Jun
(College of Automation and Information Engineering, Xi'an University of Technology, Xi'an, 710048, China)
Foundation item: The Fundamental Research Funds for the Shaanxi Natural Science. (No.2019JM-251)
Abstract: A high detectivity organic photodetector with active layer P3HT:PBDT-TT-C:PC61BM covering the visible wavelength range was prepared by solution spin coating and high vacuum evaporation. The effects of PBDT-TT-C doping P3HT:PC61BM on the optical properties of the active layer films were investigated by atomic force microscopy, UV-visible absorption spectroscopy and fluorescence spectroscopy. It was found that when the mass ratio of P3HT:PBDT-TT-C:PC61BM in the active layer was 8:2:10, the response spectrum of the active layer was broadened to 350~780 nm. The optical responsiveness and external quantum efficiency of the red, green and blue primary colors of the detector under the bias of -1 V reached 422 mA/W, 464 mA/W, 286 mA/W and 83%, 108%, 77%, respectively, and the specific detectivity reached above 1012 Jones. The results show that the organic material with an organic material complementary is doped. On the basis of ensuring the microscopic morphology of the film, By adjusting the mass ratio of the ternary mixed material, not only the carrier generation and transport can be optimized, the photocurrent of the device is improved, but also the crystallization of the thin film can be promoted by the incorporation of the third component, and the dark current of the device can be reduced.
Key words: Organic photodetector    Ternary heterojunction    Fluorescence spectroscopy    Energy transfer    PBDT-TT-C
OCIS Codes: 040.5160;230.3670;230.0040;190.4180;190.4710
0 引言

1 器件制备及表征

 图 1 有机光电探测器 Fig.1 Organic photodetector

 $R=\frac{J_{\mathrm{ph}}}{P_{\mathrm{in}}}=\frac{J_{\mathrm{light}}-J_{\mathrm{dark}}}{P_{\mathrm{in}}}$ (1)
 $D^{*}=\frac{R}{\sqrt{2 e J_{\text {dark }}}}$ (2)
 $\mathrm{EQE}=1240 \frac{R}{\lambda}$ (3)

2 结果与讨论 2.1 活性层光学特性

 图 2 薄膜的吸收光谱 Fig.2 Absorption spectra of films

 图 3 不同质量比的三元混合薄膜二维和三维AFM图 Fig.3 2D and 3D AFM images of ternary mixed films of different mass ratios

2.2 器件电学特性

 图 4 红、绿、蓝三基色光照下和暗条件下的电流密度-电压特性曲线 Fig.4 The J-V characteristics of OPDs under the illumination of red, green, blue light and in the dark condition, respectively

 图 5 不同质量比的三元OPDs的平均比探测率(D*)和平均光响应度(R) Fig.5 Average ratio detection rate (D*) and average optical responsivity (R) of ternary OPDs with different mass ratios

 图 6 三元混合活性层中μh随P3HT:PBDT-TT- C:PC61BM质量比的变化曲线 Fig.6 Curve of μh with P3HT:PBDT-TT-C:PC61BM mass ratio in ternary mixed active layer

 图 7 P3HT和PBDT-TT-C薄膜的吸收光谱以及在525 nm激发光下的PL光谱 Fig.7 Absorption spectra of P3HT and PBDT-TT-C films and PL spectra at 525 nm excitation light
 图 8 不同质量比的P3HT:PBDT-TT-C薄膜在525 nm激发光下的发光特性 Fig.8 PL properties of P3HT:PBDT-TT-C films with different mass ratios at 525 nm excitation

 图 9 不同质量比例的P3HT:PBDT-TT-C:PC61BM薄膜在525 nm激发光下的PL特性 Fig.9 PL characteristics of different mass ratios of P3HT: PBDT-TT-C:PC61BM film at 525 nm excitation light
 图 10 活性层中串联电阻随PBDT-TT-C质量比的变化曲线 Fig.10 Curve of series resistance in active layer with PBDT-TT-C mass ratio

 图 11 三基色瞬态响应曲线 Fig.11 Three primary color transient response curve

※最优OPDs对应的特性参数由8个独立器件的平均值获得

 图 12 OPDs倍增机理分析 Fig.12 Analysis of OPDs multiplication mechanism
3 结论