High-efficiency HTL-free i-n versus p-i-n InGaN single junction solar cells: A SCAPS-1D optimization study

Indium gallium nitride (InGaN) is a promising photovoltaic material due to its excellent optoelectronic properties. The conventional hole transport layer-based (HTL-based) p-i-n junction InGaN structure has been overemphasized for decades. However, the HTL (p-type layer) is parasitic, increases production cost, and device complexity. This work compares the power conversion efficiency (PCE) of the HTL-free i-n junction with the conventional HTL-based p-i-n InGaN configuration. Optimization of various parameters results in an enhanced PCE of 32.75%, which is 2.38% greater than the traditional p-i-n counterpart with a PCE of 31.99%, suggesting that the use of an HTL is dispensable. A very low HTL thickness was essential to reduce parasitic losses arising from high light absorption and poor carrier collection in the p-i-n junction device. Meanwhile, the absence of the HTL in the i-n structure results in a slight boost in PCE. The optimized p-i-n architecture demonstrates lower PCE values at temperatures below and above 300 K (27 ℃ ) compared to the HTL-free configuration. The PCE of the optimized HTL-free i-n junction slightly increases from 32.75% to 33.38% for the initial temperature rise 300–400 K before beginning to decline, suggesting its superior thermal stability due to the absence of the poor conducting and defective p-type HTL. • The i-n and p-i-n homojunction InGaN solar cells were simulated by SCAPS-1D. • The simple HTL-free i-n junction InGaN solar cell is demonstrated for the first time. • The i-n device delivered higher PCE of 32.75% compared to the p-i-n junction. • The p-type HTL is parasitic and rather dispensable in the planar p-i-n structure. • The present results compete with published works on p-i-n junction devices.