Utpal Gangopadhyay

State of Art of Solar Photovoltaic Technology

Solar electricity is more expensive than that produced by traditional sources. But over the past two decades, the cost gap has been closing. Solar photovoltaic (SPV) technology has emerged as a useful power source of applications such as lightning, meeting the electricity needs of villages, hospitals, telecommunications, and houses. The long and increasing dominance of crystalline silicon in photovoltaic (PV) market is perhaps surprising given the wide variety of materials capable of producing the photovoltaic effect. PV based on silicon wafers has captured more than 90% market share because it is more reliable and generally more efficient than competing technologies. The crystalline silicon PV is reliable as far as long term stability in real field but it is not economically viable due to starting material silicon itself costly. But still, research continues on developing a diverse set of alternative photovoltaic technology. Now PV technology is being increasingly recognized as a part of the solution to the growing energy challenge and an essential component of future global energy production. In this paper, we give a brief review about PV technology particularly crystalline silicon PV including the world and Indian PV scenarios.

Comparative simulation study between n- type and p- type Silicon Solar Cells and the variation of efficiency of n- type Solar Cell by the application of passivation layer with different thickness using AFORS HET and PC1D.

In this paper, comparative study of p type and n type solar cells are described using two popular solar cell analyzing software AFORS HET and PC1D. We use SiNx layer as Antireflection Coating and a passivated layer Al2O3 .The variation of reflection, absorption, I-V characteristics, and internal and external quantum efficiency have been done by changing the thickness of passivated layer and ARC layer, and front and back surface recombination velocities. The same analysis is taken by imposing surface charge at front of n-type solar Cell and we get 20.13%-20.15% conversion efficiency.

A Clue to Understand Environmental Influence on Friction and Wear of Diamond-Like Nanocomposite Thin Film

The wear and friction of diamond-like nanocomposite (DLN) film have been investigated in air with different relative humidity (RH), under deionized (DI) water and saline solution. The structure of the film has been characterized by Fourier transform infrared (FTIR), Raman spectroscopy, and scanning electron microscope (SEM). The result shows two interpenetrating network structure: a–C:H and a–Si:O, and they are interpenetrated by Si–C bonding. The tribological performance has been measured using ball-on-disc tribometer with tungsten carbide ball as counterbody at 10 N normal load. Results show that with increasing relative humidity (RH) from 35% to 80%, the coefficient of friction (COF) increases gradually from 0.005 to 0.074, whereas with increasing RH the wear factor decreases from mm3/Nm and attains a minimum value of mm3/Nm at 50% RH. With further increase of RH the wear factor increases again. Moreover, in DI water and especially in saline solution, both the COF and wear factor have been found to be significantly low. A clue has been interpreted to understand environmental dependency, considering the effect of surface dangling bonds, charge transfer, and chemical interactions.

Anti-reflective nanocomposite based coating for crystalline silicon solar cells with noticeable significance

Novel Diamond-like Nanocomposite (DLN) thin film as Anti-Reflective Nanocomposite Based (ARNAB) coating for crystalline silicon (c-Si) solar cell is the main objective of this paper. The DLN film was deposited by plasma assisted chemical vapour deposition (PACVD) method and characterized by Fourier transform infrared, field emission scanning electron microscope, and high resolution transmission emission microscope. Results show that c-Si3N4 and c-SiC nanoparticle (3–5 nm) were embedded in a-C:H matrix, and they were interpenetrated by Si-C bonding, i.e., typical DLN structure. The optical properties of the film were investigated by UV-VIS-near-infrared and photoluminescence spectroscopy. The performance of ARNAB coating was evaluated by measuring the reflectance, external quantum efficiency (EQE), and conversion efficiency. The solar weighted average reflection from textured c-Si was reduced to 2.25% in wavelength range 300 nm–1100 nm, and more than 90% EQE of the solar cell was achieved within the broad ...

Feasibility of n-type crystalline silicon wafer for fabricating Industrial Silicon Solar Cell with significant acceptable efficiency in near future

We are presenting the feasibility study on the industrial solar cell processing with n-type crystalline silicon. For the performing feasibility study, we have introduced SWOT (strength-Weakness-Opportunities, & Threat) analysis of crystalline solar cell with n-type crystalline silicon. Cost comparison of crystalline silicon p- type wafer and n-type wafer has also been given in this paper for better understanding the cost benefit of the total integrated crystalline silicon production line. An additional motivation for highlighting of already existing industrial process sequence for n-type silicon is incorporating in this paper.

Frequency response of Diamond-like Nanocomposite thin film based MIM capacitor and equivalent circuit modelling

The frequency response of metal-insulator-metal (MI M) based thin film capacitors were studied using LCR bridge where diamond-like nanocomposite ( DLN) film behaves as a dielectric medium. The films were deposited by plasma assisted chemical vapour d eposition (PACVD) method. Fourier transforms infrar ed spectroscopy (FTIR) and Raman spectroscopy give the structure of DLN film. The results show that, equi valent parallel capacitance (EPC) decreases sharply beyond 10 5 Hz for thinner films. But for thicker films, there is no such decrease. This is due to some parasitic series resistance effect in the capacitor circuit. An equ ivalent circuit model for real capacitor has been establish ed. Moreover, there is also a small decrement in EP C with frequency and this effect increases with thickness of film. This may be due to lack of sufficient time for electron transportation through bulk DLN material. The DLN b ased thin film capacitor has a great potential for use in electronic/electrical system.

A Novel Room Temperature Ammonia Gas Sensor Based on Diamond-Like Nanocomposite/c-Silicon Heterojunction

Thin amorphous diamond-like nanocomposite (a-DLN) films are deposited on p-type crystalline silicon (c-Si) by plasma assisted chemical vapour deposition (PACVD) technique to use it as an ammonia (NH3) gas sensor operable at room temperature. The non-linear current–voltage (I–V) characteristic of a-DLN/c-Si heterojunction shows a very good rectifying property of the junction in air and quick sensitivity in NH3 gas at room temperature. The current output in reverse biased condition of the a-DLN/c-Si heterojunction is ~ 15 times higher in NH3 than in air. Sensor also shows a good recovery property to the original state, even at room temperature. Sensing material is characterized by using Field Emission Scanning Electron Microscope (FESEM), Fourier Transform Infrared Spectroscopy (FTIR) and UV–VIS Near-IR Spectroscopy, to understand the sensing behaviour.

Large-Area Crystalline Silicon Solar Cell Using Novel Antireflective Nanoabsorber Texturing Surface by Multihollow Cathode Plasma System and Spin-On Doping

We present 11.7% efficient p-type crystalline silicon solar cells with a nanoscale textured surface and no dielectric antireflection coating. We propose nanocrystalline-like textured surface consisting of nanocrystalline columnar structures of diameters from 50 to 100 nm and depth of about 500 nm formed by reactive-ion etching (RIE) in multihollow cathode system. This novel nano textured surface acts as an antireflective absorbing surface of c-Si abbreviate as ARNAB (antireflective nanoabsorber). Light shining on the surface of RIE-etched silicon bounces back and forth between the spikes in such a way that most of it never comes back. Radio frequency (RF) hollow cathode discharge allows an improvement of plasma density by an order of magnitude in comparison to standard RF parallel-plate discharge. Desirable black silicon layer has been achieved when RF power of about 20 Watt per one hollow cathode glow is applied for our multihollow cathode system. The RF power frequency was 13.56 MHz. The antireflection property of ARNAB textured surface has been investigated and compared with wet-textured and PECVD coated silicon samples. Solar cell using low-cost spin-on coating technique has been demonstrated in this paper. We have successfully achieved 11.7% efficient large area (98 cm2) ARNAB textured crystalline silicon solar cell using low-cost spin-on coating (SOD) doping.

Antireflective Nanocomposite Based Coating on Crystalline Silicon Solar Cells for Building-Integrated Photovoltaic Systems

Building-integrated photovoltaic (BIPV) systems represent an interesting, alternative approach for increasing the available area for electricity production and potentially for further reducing the cost of solar electricity. In BIPV systems, the visual impression of a solar module becomes important, including its color. However, the range of solar cell colours and shapes currently on offer to architects and BIPV system designers is still very limited, and this is a barrier to the widespread use of PV modules as a constructional “material.” The color of a solar module is determined by the color of the cells in the module, which is given by the antireflection coating (ARC). However, access to efficient, but differently colored, solar cells is important for the further development of BIPV systems. In this paper, we have used Diamond-like nanocomposite layer as an Antireflective Nanocomposite based (ARNAB) coating material for crystalline silicon solar cell, and the impact of varying the color of an ARC upon the optical characteristics and efficiency of a solar cell is investigated. In addition to a comparison of the optical characteristics of such solar cells, the effect of using colored ARCs on solar cell efficiency is quantified using the solar cell modeling tool PC1D.

Encapsulation of SiNWs Array with Diamond-like Nanocomposite Thin Film for Ultra-low Reflection

Silicon nanowire (SiNW) arrays were synthesized using single step metal assisted chemical etching (SSMACE) method on n-type mono crystalline silicon. The effect of encapsulation of SiNW arrays with diamond-like nanocomposite (DLN) deposited by plasma assisted chemical vapor deposition (PACVD) method has been investigated. The structural and optical properties of SiNW and DLN thin film has been studied using FESEM, FTIR and UV–VIS-NIR spectroscopy. A very low (3–4 %) and high broadband (300–1,000 nm) reflection has been achieved from SiNWs array. However, after deposition of DLN thin film on nanowire array, the reflection further reduces significantly to 1.7 %. The SiNW arrays encapsulated with DLN thin film has a great potential to use in solar cell.