The aim and objective of this work is to develop low cost, and naturally abundant semiconductor thin film materials for photovoltaic applications. In this work, different materials for window, absorbent and interfacial layers are studied. This study was done for synthesis and characterization of these thin film materials. All these materials were deposited by using thermal evaporation method. Characterization of sample material was carried out using Raman spectroscopy, X-ray diffraction (XRD), Energy Dispersive X-ray spectroscopy (EDX), UV-Vis-NIR spectrophotometer and Photoconductivity. Furthermore conductivity type determination was performed by using hot probe technique. CdS thin films were deposited at chamber ambient temperature and annealing was done in vacuum at 400 ̊C for 1 hour. Further these films were doped with Al using ion exchange method. In XRD patterns no peaks of Al and Al2S3 were found, which revealed that the incorporation of Al+3 ions does not alter the crystalline structure of these doped CdS thin films. The bandgap of CdS initially decreased for Al doping and then increased with the increase in Al concentration and finally reached a saturation value of 2.42 eV for 18 at.% of Al. All Al-doped CdS thin films showed n- type conductivity. CdTe thin films for applications as absorber layer in thin film solar cells (TFSCs) were studied. These thin films were deposited by thermal evaporation and were effectively doped with Cu by using ion exchange technique. At higher annealing temperature variation was found in size of crystallites. The obtained bandgap energy values changed from 1.53eV to 1.42eV for samples annealed at 100-400°C. The type of conductivity was concluded to be p-type for all CdTe films doped with Cu. Further in this work, to discover nontoxic absorber layer material, libraries of (SnS)x-(Bi2S3)1-x graded thin films were successfully deposited by using combinatorial synthesis approach (CSA) via thermal evaporation. Effect of annealing in vacuum and elemental composition was studied. XRD studies confirmed that these thin films are grown in different binary and ternary phases and were well crystalline; also these have better surface homogeneity, crystalline and more compact morphology. Photo conductivity response showed a shift towards smaller wavelengths (blue shift) as the temperature of annealing was increased to 400°C. It was also improved progressively for atomic ratio of Sn/Bi (0.22 to 2.11). Bandgap energy increased from 1.23 eV to 1.48 eV for variation in Sn/Bi value from 0.21 to 6.67. Films having compositions Sn/Bi > 2 and annealed at 400 ̊C showed p-type conductivity and could be used as an active photon absorber layer. In the next phase, we have studied the influence of annealing temperature on Sn-Bi-S graded thin films annealed in Argon environment. The structural and morphological properties were investigated, which showed that the thin films with different well crystallized binary phases and good surface homogeneity are grown. The estimated value of bandgap was in the range 1.27-1.43eV for Sn/Bi of 2.18-0.67. Moreover, samples annealed over temperature of 400°C -500°C showed better photoconductivity response. Photoconductivity response was better for samples containing Sn rich compositions and these showed p-type conductivity over the temperature range of 350-400 ̊C. As a part of search for nontoxic photovoltaic materials, thin films of Cu-Sn-S were successfully prepared on glass slides. Further annealing of all these samples was done in vacuum at 350̊C for two and half hours. Bandgap increased (1.07 – 1.47 eV) with increase in Cu content (7-18 at.%). Photo response also improved gradually with increasing Cu at.% in these thin films. All samples showed p-type conductivity. For development of low resistance interfacial layer, ZnTe thin films were deposited on glass slides via thermal evaporation and were effectively doped with Cu using ion exchange method. Optical bandgap decreased with annealing at 300°C, which verifies the settlement of doped Cu in ZnTe thin films. The resistivity of as doped sample was 148 Ω-cm and after annealing at 400°C for one hour it was reduced to 30 Ω-cm. The conductivity type of these Cu doped ZnTe thin films was observed to be p-type. These conclusions can help out in manufacturing of CdTe TFSCs. Our obtained results for Al doped CdS thin films with improved bandgap energy of 2.42eV are useful for utilization of these materials as window layer in different types of TFSCs such as CdTe, CZTS, SnS, etc. The results for Cu doped CdTe thin films are useful for use as absorber layer in TFSCs. Further findings of dependency of physical properties on elemental composition and annealing of (SnS)x- (Bi2S3)1-x graded thin films are useful for applications of these nontoxic materials as layer in TFSCs. Furthermore, physical properties of Cu:SnS thin films were also explored for the use of these materials as layer. Interfacial layer being an important part of TFSCs, Cu doped ZnTe thin films with low resistivity are valuable for an interfacial material at back contact.