Carrier‐Selective Contact Based Silicon Solar Cells Processed at Room Temperature using Industrially Feasible Cz Wafers

Abstract

For the broad use of solar photovoltaic devices, the device fabricated at commercially viable silicon wafers at room temperature is more preferable to harvest abundant solar energy. Silicon heterojunction solar cells at room temperature, based on carrier-selective layers without using any specified surface passivation layer on the silicon wafer is fabricated. Industrially feasible Cz n-type non-textured silicon wafers having the bulk lifetime of 300 ms are used for cell fabrication. The molybdenum oxide (MoO x ) and lithium fluoride (LiF x ) are used as hole-and electron-selective layers, respectively. The highest conversion efficiency of >15% from the simple architecture of Ag/TCO/MoO x /n-Si/LiF x /Al is achieved. The internal quantum efficiency of %96% is observed in the shorter wavelength region, whereas to understand relatively less response between 800 and 1100 nm wavelength region; effective minority carrier diffusion lengths are estimated. The authors also confirm the inversion layer formation in the silicon after MoO x contact from temperature dependent capacitance-voltage measurements, and quantify the crucial built-in-potential of %0.69 V from the cell structure due to the high work function of MoO x layer.

An all ambient, room temperature–processed solar cell from a bare silicon wafer

“…For this dilemma, the formation of a practically proper, sufficiently conducting contact at the metal electrode/Si interface requires an additional high-temperature post-annealing process after the electrode deposition. Nayak et al processed Si cells at room temperature based on the asymmetric heterocontact concept ( 10 ), but still had to use vacuumed thermal evaporation and sputtering facilities as well as a heating pretreatment ( 20 ).…”

Sub‐Stochiometric Nickel Oxide Hole‐Selective Contacts in Solar Cells: Comparison of Simulations and Experiments with Sputtered Films

“…Transition metal oxides are currently explored as hole-/ electron-selective contact options in silicon (Si) heterojunction solar cells. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] Indeed, negligible parasitic absorption, tunable electronic properties, abundance, and low-cost deposition methods make these materials attractive for optoelectronic applications. Importantly, some of the transition metal oxides exhibit n-type conductivity due to energetically favorable oxygen (anion) vacancies (e.g., MoO 3 , V 2 O 5 , WO 3 , TiO 2 ); on the other hand, oxides like NiO or Cu 2 O behave as p-type due to energetically favorable metal cation vacancies.…”

Spray deposited TiO2thin films for large-area TiO2/p-Si heterojunction solar cells

“…Carrier selective contacts (CSC) are being investigated to develop more low-cost photovoltaics (PVs) by reducing the thermal budget of the cell manufacturing process, as high temperature doping steps can be avoided in the CSC based cell fabrication [3][4][5]. Interface engineering to reduce recombination, large area deposition and low-cost fabrication methods are some of the major areas of research in carrier selective contact based heterojunction solar cells [6,7].…”