Phototransistor Behavior Based on Dye-Sensitized Solar Cell

TL;DR

This study demonstrates a dye-sensitized solar cell-based device exhibiting phototransistor-like behaviors, including distinct transport regimes and asymmetric current-voltage characteristics, driven by photo-induced processes in nanocrystalline TiO2 films.

Contribution

It introduces a novel light-controlled device based on dye-sensitized solar cells that mimics phototransistor behaviors with detailed analysis of transport and photovoltaic processes.

Findings

Identified three transport behaviors: linear, saturated, and breakdown-like.

Observed asymmetric voltage-current loops due to effective photo-conducting area differences.

Clarified the series connection of dark and photovoltaic processes affecting device behavior.

Abstract

In the present work, a light-controlled device cell is established based on the dye-sensitized solar cell using nanocrystalline TiO2 films. Voltage-current curves are characterized by three types of transport behaviors: linear increase, saturated plateau and breakdown-like increase, which are actually of the typical performances for a photo-gated transistor. Moreover, an asymmetric behavior is observed in the voltage-current loops, which is believed to arise from the difference in the effective photo-conducting areas. The photovoltaic voltage between the shared counter electrode and drain (VCE-D) is investigated as well, clarifying that the predominant dark process in source and the predominant photovoltaic process in drain are series connected, modifying the electric potential levels and thus resulting in the characteristic phototransistor behaviors.