基于单壁碳纳米管(SWCNT)/单层石墨烯/GaAs双异质结结构构筑了自驱动近红外光电探测器, 利用GaAs优异的光电特性和石墨烯的高载流子迁移率特点, 该光电探测器在无偏压情况下光电响应率可达393.8mA/W, 比探测率达到6.48×1011Jones, 开关比为103。而且, 利用半导体性SWCNT对近红外光子的高吸收特性以及SWCNT/石墨烯异质结对SWCNT产生光生载流子进行有效分离, 使得该双异质结光电器件的光谱响应可拓展至1064nm, 突破了GaAs自身的响应极限860nm。

In this work, we investigated the effect of single walled carbon nanotubes (SWCNT) on the electrical and photovoltaic properties of methyl red (MR) dye based photoelectrochemical cell (PEC). MR dye based PEC with LiClO₄ as ion salt were fabricated with and without mixing SWCNT. The cells were characterized through electrical and optical measurements. The performance of the devices changed drastically in presence of SWCNT. The transition voltage and trap energy of the cells were estimated from the steady-state dark current voltage (I-V) analysis. The transition voltage and trap energy decreased for MR dye cell in presence of SWCNT. Open circuit voltage (V_oc), short circuit current (J_sc), fill factor (FF) and power conversion efficiency (η) increased due to the addition of SWCNT. Further measurement of the transient photocurrent showed that the growth and decay of photocurrent was quite faster in presence of SWCNT. The photocurrent decay with time was fitted for both the cells and found to follow a power law relation which indicates dispersive transport mechanism with exponential trap states distributed in between lowest unoccupied molecular orbital (LUMO) and highest occupied molecular orbital (HOMO) levels. Possible interpretation is done on the lowering of trap energy with the photocurrent. These results suggest that SWCNT lowers the trap energy of the cells by providing efficient percolation pathways for the conduction of charges. It is expected that due to lowering of trap energy the residing time of the free carriers within the traps decreases. In other words, it may also be said that the charge recombination decreases. These factors affect the overall conduction of charges and improve the electrical and photovoltaic properties.