|
Recent advances in solar cells and photo-electrochemical water splitting by scanning electrochemical microscopy
Xiaofan ZHANG, Man LIU, Weiqian KONG, Hongbo FAN
Front. Optoelectron.. 2018, 11 (4): 333-347.
https://doi.org/10.1007/s12200-018-0852-7
Investigation on the mechanism and kinetics of charge transfer at semiconductor/electrolyte interface is significant for improving the photoelectric conversion efficiency and developing novel and high-efficiency photovoltaic devices. Scanning electrochemical microscopy (SECM), as a powerful analytical technique, has a potential advantage of high spatial and temporal resolution. It has been expanded into a broad range of research fields since the first inception of SECM in 1989 by Bard groups, which includes biological, enzymes, corrosion, energy conversion and storage (such as solar cells, hydrogen and battery). Herein, we review the basic principles and the development of SECM, and chiefly introduce the recent advances of SECM investigation in photoelectrochemical (PEC) cells including solar cells and PEC water splitting. These advances include rapid screening of photocatalysts/photoelectrodes, interfacial reaction kinetics and quantitation of reaction intermediates, which is significant for evaluating the performance, choosing catalysts and developing novel composite photoanodes and high efficiency devices. Finally, we briefly describe the development trends of SECM in energy research.
Figures and Tables |
References |
Related Articles |
Metrics
|
|
Ether chain functionalized fullerene derivatives as cathode interface materials for efficient organic solar cells
Jikang LIU, Junli LI, Guoli TU
Front. Optoelectron.. 2018, 11 (4): 348-359.
https://doi.org/10.1007/s12200-018-0842-9
The electron transport layer (ETL) plays a crucial role on the electron injection and extraction, resulting in balanced charge transporting and reducing the interfacial energy barrier. The interface compatibility and electrical contact via employing appropriate buffer layer at the surface of hydrophobic organic active layer and hydrophilic inorganic electrode are also essential for charge collections. Herein, an ether chain functionalized fullerene derivatives [6,6]-phenyl-C61-butyricacid-(3,5-bis(2-(2-ethoxyethoxy)-ethoxy)-phenyl)-methyl ester (C60-2EPM) was developed to modify zinc oxide (ZnO) in inverted structure organic solar cells (OSCs). The composited ZnO/C60-2EPM interface layer can help to overcome the low interface compatibility between ZnO and organic active layer. By introducing the C60-2EPM layer, the composited fullerene derivatives tune energy alignment and accelerated the electronic transfer, leading to increased photocurrent and power conversion efficiency (PCE) in the inverted OSCs. The PCE based on PTB7-Th:PC71BM was enhance from 8.11% on bare ZnO to 8.38% and 8.65% with increasing concentrations of 2.0 and 4.0 mg/mL, respectively. The fullerene derivatives C60-2EPM was also used as a third compound in P3HT:PC61BM blend to form ternary system, the devices with addition of C60-2EPM exhibited better values than the control device.
Figures and Tables |
References |
Related Articles |
Metrics
|
|
Efficient deep red phosphorescent OLEDs using 1,2,4-thiadiazole core-based novel bipolar host with low efficiency roll-off
Runda GUO, Wenzhi ZHANG, Qing ZHANG, Xialei LV, Lei WANG
Front. Optoelectron.. 2018, 11 (4): 375-384.
https://doi.org/10.1007/s12200-018-0855-4
A series of 1,2,4-thiadiazole core-based bipolar materials, 2,2'-(1,2,4-thiadiazole-3,5-diyl)bis(N,N-diphenylaniline) (o-TPATHZ), 3,3′-(1,2,4-thiadiazole-3,5-diyl)bis(N,N-diphenylaniline) (m-TPATHZ) and 4,4'-(1,2,4-thiadiazole-3,5-diyl)bis(N,N-diphenylaniline) (p-TPATHZ) were developed as the host matrixes for the deep red phosphorescent emitters tris(1-phenylisoqiunoline)iridium (Ir(piq)3) and [bis(2-methyldibenzo-[f,h]-quinoxaline)Ir(III)(acetylacetonate)] (Ir(MDQ)2(acac)). By systematic studying, we demonstrated that there are two types of charge-trapping effect within the emissive layers through adjusting the host-guest compatibility. And, it is revealed that a symmetric charge-trapping effect can contribute to realizing a stable charge-balance, which led to a mitigating efficiency roll-off at high current density. Consequently, a maximum external quantum efficiency (EQE) of 16.2% was achieved by an optimized device with p-TPATHZ-Ir(piq)3 emissive layer. Remarkably, the EQE still remained as high as 15.7% at the high luminance of 1000 cd/m2.
Figures and Tables |
References |
Related Articles |
Metrics
|
|
Temperature dependence simulation and characterization for InP/InGaAs avalanche photodiodes
Yanli ZHAO, Junjie TU, Jingjing XIANG, Ke WEN, Jing XU, Yang TIAN, Qiang LI, Yuchong TIAN, Runqi WANG, Wenyang LI, Mingwei GUO, Zhifeng LIU, Qi TANG
Front. Optoelectron.. 2018, 11 (4): 400-406.
https://doi.org/10.1007/s12200-018-0851-8
Based on the newly proposed temperature dependent dead space model, the breakdown voltage and bandwidth of InP/InGaAs avalanche photodiode (APD) have been investigated in the temperature range from -50°C to 100°C. It was demonstrated that our proposed model is consistent with the experimental results. Our work may provide a guidance to the design of APDs with controllably low temperature coefficient.
Figures and Tables |
References |
Related Articles |
Metrics
|
|
A direct method to calculate second-order two-dimensional terahertz spectroscopy in frequency-domain based on classical theory
Feidi XIANG, Kejia WANG, Zhengang YANG, Jinsong LIU, Shenglie WANG
Front. Optoelectron.. 2018, 11 (4): 413-418.
https://doi.org/10.1007/s12200-018-0863-4
Previous theoretical researches on the two-dimensional terahertz spectroscopy (2DTS), which are conducted via inefficiently time-consuming numerical simulation, deal with only single-mode system. To overcome the limitations, we derive a classical-theory-based analytical solution which is applicable to multi-modes system. Three typical weak sources of nonlinearities are introduced. The findings suggest that the analytical results correspond well with those obtained by the traditional numerical simulation. Thus the study provides a more efficient and practical method to directly calculate 2DTS, and, in a broader sense, sheds new light on the theory of 2DTS.
Figures and Tables |
References |
Related Articles |
Metrics
|
12 articles
|