In 2017, Kaneka Corporation in Japan realized heterojunction back contact (HBC) solar cell with an efficiency of up to 26.7% (JSC of 42.5 mA·cm −2) 25, 26, and recently, LONGi Corporation in China has announced a new record efficiency of 27.30% 16.
Silicon heterojunction (SHJ) solar cells have achieved a record efficiency of 26.81% in a front/back-contacted (FBC) configuration. Moreover, thanks to their advantageous high VOC and good infrared response, SHJ solar cells can be further combined with wide bandgap perovskite cells forming tandem devices to enable efficiencies well above 33%.
Heterojunctions can increase the efficiency of solar cell devices relative to homojunctions, but there is a large parameter space with significant tradeoffs that must be considered.
The prominent examples are low-thermal budget silicon heterojunction (SHJ) solar cells and high-thermal budget tunnel-oxide passivating contacts (TOPCon) or doped polysilicon (poly-Si) on oxide junction (POLO) solar cells (see Fig. 1 (e)– (g)).
Although many excellent works have been done in solar cells based on ZnO heterojunction arrays, there are still some limiting factors in the development of solar cells, such as low PCE, short lifetime of solar cells, material instability, high cost and toxicity of materials.
Provided by the Springer Nature SharedIt content-sharing initiative Crystalline-silicon heterojunction back contact solar cells represent the forefront of photovoltaic technology, but encounter significant challenges in managing charge carrier recombination and transport to achieve high efficiency.