Feasibility of combining p-type crystalline Si (c-Si) of 200―8000 nm in thickness with an n-type bismuth sulfide (Bi 2 S 3 ) thin film of 300 nm in thickness for thin film solar cell is analyzed. Theoretical analysis shows that the high optical absorption coefficient (10 5 cm ―1 ) of Bi 2 S 3 results in a light-generated current density (J L ) of >20 mA/cM 2 for a c-Si(200 nm)Bi z S 3 (300 nm) stack at a combined film thickness of 500 nm, and with an open circuit voltage (V oc ) of nearly 600 mV. Proof-of-concept cell structures were prepared on p-type c-Si wafers of electrical resistivity 1 Ω cm. Any oxide layer at the interface significantly deteriorates the cell parameters. In a cell prepared using evaporated n-Bi 2 S 3 on (p) c-Si, J sc is 3 mA/cm 2 ; V oc is 360 mV; and η is 0.5%; which improved to: 7.2 mA/cm 2 , 485 mV and 1.7%, respectively, after heating the cell in forming gas. A cell with an Sb 2 S 3 (40 nm) thin film as an antireflective coating on Bi 2 S 3 , produced: J sc of 10 mA/cm 2 ; V oc of 480 mV; and η of 2.4%. Theoretical simulation suggests that better cell fabrication could lead to: J sc of 26 mA/cm 2 ; V oc of 600 mV; and η of 10%.

http://jes.ecsdl.org/content/158/7/H741.full.pdf

Analysis of a Bismuth Sulfide/Silicon Junction for Building Thin Film Solar Cells

ABSTRACT Carbon fiber-reinforced polymer (CFRP) is an engineering composites with excellent performance. The adhesion strength of nickel layer on CFRP composite was enhanced by pretreatment processes, including sandblasting and activation. The surface roughness, wettability, phase and microstructure of the CRFP and the layer were determined by surface profile-meter, goniometer, X-ray diffraction and scanning electronic microscopy, respectively. The adhesion force of nickel layer on CFRP composite was estimated by 3 M tape and pull-out test. The results showed that electroless nickel layer was composed of crystalline phase with small grain size, which belonged to medium-phosphorus deposits. The sandblasting improved the surface roughness and wettability of CFRP surface and rendered hydrophobic surface hydrophilic. The surface roughness of CFRP composites after sandblasting was enhanced by about 60.2%, at the same time the adhesion strength of the layer metalized CFRP composites after sandblasting was improved by 131%. After 3 M tape test, the adhesion state of nickel-CFRP composites with and without sandblasting could be qualitatively classified as grade 5B and 1B, respectively. The good adhesion of nickel layer on CFRP composite was generated from the increase in the surface roughness of CFRP composites after sandblasting and chemical activation, resulting in hydrogen bonds and covalent bonds. The lightning strike test showed that electroless nickel layer did not provide sufficient protection for the sandblasted CFRP composite when subjected to an big impulse current of up to 40 kA current peak and 8–20 μs duration due to the high electrical resistivity.

Adhesion enhancement for nickel layer deposited on carbon fiber reinforced polymer (CFRP) composites by pretreatment processes for lightning strike

Interest in the metallization of dielectric substrates such as ceramics, plastics is growing because of their wider applications in electronic industries, namely in the fabrication of MIC's, HIC's etc. In this paper an attempt has been made to deposit copper and nickle using room temperature electroless baths on pre-selected areas of alumina and FRP substrates using PdCl2 as activator. The process offers a uniform dense deposit of Ni/Cu selectively on the substrates. For full coverage of the metal on the substrate it has been found that either AgNO3 or PdCl2 as activator has the same effect. The process yields a dense deposit of Cu and Ni having good adherence to the substrates.

T. Acharjee

Papers

Photoselective Deposition of Copper and Nickel on Non-Conducting Substrates by Alkaline Electroless Baths at Room Temperature

Properties of amorphous Bi2S3-crystalline silicon heterojunctions