Metal oxide-based heterojunction thin films for solar cell applications

The interest and development in a fully green future towards sustainable technology and environmental preservation has spurred exponentially for the past few years. The adoption in clean energy is underway with solar photovoltaic (PV) technology leading the race. To keep PV sector competitive with current conventionally generated electricity, an alternative economic PV module using cheap materials with low-cost deposition method is needed. Among the candidate, metal oxides (MO) semiconductors are great potential materials to achieve this goal due to its massive availability, non-toxicity, chemically stable, and can be deposited using low-cost techniques at ambient condition. In this report, the p-n junction solar cell was fabricated using layer by layer deposition of n-type and p-type metal oxide semiconductors. Co
₃
O
₄
and CuO were used as absorbing layers and ZnO as a window layer in contact with each other using simple spin coating deposition method. Photocurrent density (J
_SC
), photo voltage (V
_OC
) and the crystallinity of materials were investigated to characterize their optoelectronic properties. It is observed that Co
₃
o
₄
shows larger crystallite size compared to CuO at 26.66 nm and 24.86 nm, respectively. Samples consisting of Co
₃
<;span style="font-size: 15px;"> O<;/span>
₄
and CuO p-n junction solar cell exhibits high absorbance in the visible spectral region of 350 nm to 750 nm. J-V measurement shows that FTO/ZnO/Co
₃
O
₄
/In heterojunction films exhibits short-circuit current density of 0.391 mA/cm
^-1
and open-circuit voltage of 0.476 V under the illumination of AM1.5 solar simulation (100mW/cm
²
). Meanwhile, FTO/ZnO/CuO/In shows short-circuit current density of 0.429 mA/cm
^-1
and open-circuit voltage of 0.048 V. Thus, it shows that green materials without any environmental issue has high potential in solar cells application.