- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Carrier transport and recombination dynamics of InAs/GaAs sub-monolayer quantum dot near infrared photodetector
摘要： Here, we present a relative study of tunnel-induced photocarrier escape processes in a laterally coupled InAs sub-monolayer quantum dot-based photodetector (SML QD-PD) as a function of fractional coverage from 0.4 ML to 0.8 ML. Both by simulation and experiment, we have quantitatively described the temperature dependent interband photoresponse spectrally tuned in the near infrared region (835 nm–890 nm) on the basis of mutual competition between the interband carrier recombination and interdot tunneling lifetime with varying SML coverage. The progressively increasing recombination lifetime and decreasing interdot tunneling lifetime with increasing SML coverage has attributed to a faster photoresponse and greater responsivity. At higher coverage fraction, tunnel induced fast speed photocarrier transit through lateral array of SML QDs has been found to be capable of offering a faster temporal response (100 μs) with faithful reproducibility up to higher frequencies (1.3 KHz). Here, we report a powerful strategy to simultaneously tune responsivity, speed of time response and detectivity by externally controlling the SML coverage. This time response is measured to be nine times faster than a conventional SK QD photodetector. With increased coverage, inhibition of dark current due to trapping of injected charge carriers up to higher temperatures have resulted in high sustainable photodetectivity of 8 × 1011 cm Hz1/2 w?1 at ~250 K that offers near room temperature photodetection.
关键词： photoconductive gain,quantum dot photodetector,inter-dot tunneling,submonolayer coverage,near-infrared photoresponse,recombination dynamics,temporal photoresponse
更新于2025-09-23 15:19:57
-
Ultrafast spectroscopic investigation of the effect of solvent additives on charge photogeneration and recombination dynamics in non-fullerene organic photovoltaic blends
摘要： The PBDB-TF:IT-4F blend is a kind of state-of-the-art non-fullerene photovoltaic blend. Herein, the effects of 1,8-diiodooctane (DIO) and 1-chloronaphthalene (CN) additives on the neat and blend film morphologies and the related ultrafast photophysical processes are studied. It is found that both DIO and CN can lead to an enhanced structural order in the in-plane direction and increased average lifetime of excitons in neat PBDB-TF films. The face-on orientation of PBDB-TF still exists in the DIO-processed PBDB-TF:IT-4F blend film, while in the case of the CN-processed blend film, molecular packing orientation is similar to that of the pristine blend film. The blend samples prepared with the two additives show increased initial exciton yields. Interestingly, in the blend samples prepared with the DIO additive, the recombination loss via the formation of polymer triplet excitons can be effectively suppressed, in comparison to the pristine and CN-processed samples. Both the DIO- and CN-processed devices show increased short-circuit current densities. The DIO-processed device is also found to have a superior fill factor due to suppressed recombination loss. The work provides a comprehensive insight into the ultrafast photophysical processes in varied blend morphologies induced by additives and their effect on the photovoltaic parameters of the devices.
关键词： charge photogeneration,ultrafast spectroscopy,recombination dynamics,solvent additives,non-fullerene photovoltaic blend
更新于2025-09-23 15:19:57
-
Effects of interfacial energy level alignment on carrier dynamics and photovoltaic performance of inverted perovskite solar cells
摘要： Metal doping is an efficient method for optimizing NiOx as hole transport material in the inverted perovskite solar cells, which can contribute to the optimization of the interfacial energy level alignment, while the underlying influencing mechanism on the charge carrier dynamics and device performance needs to be further elucidated. In this work, NiOx films with modulated energy levels are obtained via Li doping and examined by ultraviolet photoelectron spectrometer. The effects of the energy level alignment of NiOx on the carrier transfer and recombination dynamics are elucidated by transient photovoltage/photocurrent and transient fluorescence dynamics. The Li doping can significantly shift the valence band of NiOx downward, and the 4% Li content endows NiOx with the optimal energy level matching with perovskite and the best charge separation/transfer ability, which can be confirmed through the photoluminescence results. The corresponding device possesses superior photovoltaic parameters with the champion power conversion efficiency of 17.34%, 37% higher than device based on pure NiOx. The results highlight that proper metal doping can optimize the energy level of the hole transport material to well match the perovskite, thus efficiently promoting charge separation and inhibiting charge recombination, which leads to the enhancement of the device performances.
关键词： Li-doped NiOx,Inverted perovskite solar cell,Charge transport/recombination dynamics,Energy level alignment
更新于2025-09-19 17:13:59