Enue Barrios-Salgado

PbSe Thin Films in All-Chemically Deposited Solar Cells

We report on PbSe thin films serving as an absorber in solar cell structures, CdS(100 nm)/Sb 2 S 3 (250 nm)/PbSe(100―250 nm). The cells are prepared by sequential chemical deposition of the films on a commercial SnO 2 :F coated sheet glass. These cells show V oc of 690 mV and J sc of 3.5 mA/cm 2 and a conversion efficiency of 0.69% under sunlight. Two distinct routes are taken to deposit PbSe thin films of 100-250 nm thickness: N,N-dimethylselenourea (SU) or sodium selenosulfate (SS) as the source of selenide ions in the bath. These films are p-type with an electrical conductivity of 0.5 (Ω cm) ―1 and optical bandgaps of 0.68 eV (SU) and 0.85 eV (SS) at a film thickness of 150 nm. Without the PbSe absorber, a CdS/Sb 2 S 3 cell has V oc of 595 mV, but its J sc is low, 0.003 mA/cm 2 . In CdS/Sb 2 S 3 /PbSe (SU or SS) cells, J sc is higher by a factor of thousand, and it is consistently higher for a larger PbSe film thickness. Thus, PbSe performs the role of a p + optical absorber in the cell, contributing to the J sc of the cell.