| 초록 |
Ever since the keserite Cu2ZnSnSe4 (CZTS) thin film solar cells recorded the highest efficiency of 12.6%, the device performance has reached a plateau due to the high open-circuit voltage (Voc) deficit (Eg/q-Voc, where q is the elemental charge), which are considered to be originated from the fluctuation of band structures and non-radiative recombination centers in CZTS solar cells. Here, we applied a passivation strategy to the surrounding interfaces of the CZTS absorber by inserting a thin ALD-grown dielectric layer on top of the CZTS and a nano-patterned dielectric layer between the CZTS and the Mo. As a result, Voc was significantly improved; the Voc-deficit value is comparable to that of the world record CZTS solar cell. Structural, chemical, and electronic properties were studied using scanning electron microscopy, transmission electron microscopy, energy dispersive x-ray spectroscopy, low-temperature photoluminescence, and secondary ion mass spectroscopy. We also studied the effects of interface passivation in correlation with the device performance after J-V and external quantum efficiency measurement. |
