Application of bidirectional (up and down)-conversion luminescence material (GdBO3:Yb3+/Tb3+) in CdSe0.4S0.6 quantum dot-sensitized solar cells

A novel bidirectional (up and down)-conversion luminescence agent (GdBO3:Yb3+/Tb3+), that can convert ultraviolet lights and near-infrared lights into visible lights, is employed to enhance the light capture capability of CdSe0.4S0.6 quantum dot-sensitized solar cells (QDSSCs). In this study, the GdBO3:Yb3+/Tb3+@TiO2 photoanode is fabricated by sol-gel drop-coating method. And then, the CdSe0.4S0.6 quantum dots (QDs) are deposited on the prepared photoanode surface by successive ionic layer adsorption and reaction (SILAR) technique at room temperature. The photoelectric measurements show that the light capture capability of the CdSe0.4S0.6 QDSSCs device can be obviously enhanced after adding GdBO3:Yb3+/Tb3+ nanoparticles and the CdSe0.4S0.6/GdBO3:Yb3+/Tb3+@TiO2 photoanode with 1.0% adding amount of GdBO3:Yb3+/Tb3+ displays the highest photovoltaic performance. The presence of GdBO3:Yb3+/Tb3+ nanoparticles makes CdSe0.4S0.6 QDs indirectly utilize ultraviolet lights and near-infrared lights in solar lights. In addition, the scattering effect of GdBO3:Yb3+/Tb3+ nanoparticles in TiO2 films can cause the reflection of the incident lights. The reflected lights can also be absorbed by the CdSe0.4S0.6 QDs, increasing light capture capability. The research results demonstrate a potential applied value of bidirectional (up and down)-conversion luminescence agent in QDSSCs.