| Abstract [eng] |
Telecommunications Physics and Electronics POLYCRYSTALLINE SILICON SOLAR CELL CONTACT OPTIMIZATION Donatas Bakutis Supervisor Dr. Lina Petrėnienė Department of Radiophysics, Faculty of Physics, Vilnius University. Vilnius; 2016. 52 p. Purpose of the work. To optimize screen printed front contacts, comparing five different silver pastes by comparing their electrical and optical properties; to investigate and compare the back side aliuminium paste with reference paste; to investigate how the back surface force (BSF) influences the electrical parameters of the SE. Methods. All experiments were carried out in a commercial plant conditions. In experiments metallization process used to screen-printing technology. Were compared five different front side silver pastes (A, B, C, D, E) when using three different screens (A, B, C). In the other experiment, during the formation of a silicon solar cell, an aluminum pastes (G and H) are generally screen printed and dried on the back side of the silicon wafers. The wafers are then fired to form an Al-Si melt. Then electrical parameters and thickness of back surface field of wafers with different aluminum pastes were measured compared. Results of The Research. A comparison of the five front side silver pastes the results obtained show that the efficiency of the SE is the largest η = 17.65 %, while the effective optical power loss is the lowest pvisi = 8.67 %. This is obtained with the E paste and B screen. The results show that the coefficient of performance is not entirely dependent on the calculated loss. This can result in the fact that the calculation of losses are not taken into account with a metal semiconductor junction resistance losses, recombinant losses and light reflected from the edges of the contact, when applied to solar cells and absorbed. The results show that (A) and (E) pastes contacts are more equal than the other tested pastes, investigated the difference between the narrowing and widening of contacts are from 10 to 17% and (B), (C) and (D) pastes contacts are uneven, the difference between the narrowing and widening of contacts are from 31 to 40%, this could result in different rheological properties. A comparison of the rear side of the aluminum pastes the results show that the efficiency is the highest η = 17.63% with (H) rear aluminum paste; it could affect the thickness of the back surface field layer (BSF). Conclusions. Investigated that the efficiency of solar cell is the highest η = 17.65%, while the effective optical power loss is the lowest pvisi = 8.67 %. This is obtained with the E paste and B screen. Investigated that (A) and (E) pastes contacts are more equal than the other tested pastes, the difference between the narrowing and widening of contacts are from 10 to 17% and (B), (C) and (D) pastes contacts are from 31 to 40%, this could result in different rheological properties. Investigated that the efficiency is the highest η = 17.63% with (H) rear aluminum paste. |
