EXPLOITATION OF GRAPHENE OPTOELECTRONICS PROPERTIES AS CARRIER BOOSTER LAYER AND EFFECTIVE CHARGES TRANSPORT MEDIUM IN THIN FILM ?C-SIOX:H BASED SOLAR CELLS

This dissertation research discusses a specific problem related to the dynamics of carrier production (electron-hole pair), effective media of charge transport as well as their interface properties in ?c-SiOx:H based solar cell device by involving graphene sheet (GS) as a solution to optimize the pe...

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Bibliographic Details
Main Author: Rosikhin, Ahmad
Format: Dissertations
Language:Indonesia
Subjects:
Online Access:https://digilib.itb.ac.id/gdl/view/46651
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Institution: Institut Teknologi Bandung
Language: Indonesia
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Summary:This dissertation research discusses a specific problem related to the dynamics of carrier production (electron-hole pair), effective media of charge transport as well as their interface properties in ?c-SiOx:H based solar cell device by involving graphene sheet (GS) as a solution to optimize the performance using analytic simulation technique. Carrier production is considered as essential problem in light-to-electricity conversion process due to the initial stage of output current is charge carrier generation then charges dissociate passing through the interface moves separately toward electrode to exits from the device forming a photocurrent. There are some problems leading to reduce device performance involve the lack of ability of absorber layer to absorb incident light properly. On the other hand, light prefers to reflected back compared with transmitted as well as charge collection is not sufficiently optimum. Furthermore, the internal microscopic properties of material sometimes does not has appropriate interface with other so that potentially leading to light propagation process passing through junction become more fluctuated. Other consequence due to incompatibility of its electronics structure is also affects on disturbing charge transport properties therefore it need additional material which is able to overcome the problems. The materials must have excellent both optics and electronics properties as well as interfacially flexible when layered with other thin layer unless leading to increase the risk of parasitic resistance which will burdening device performance. Graphene nanomaterial has been chosen to be exploited become a layer which able to optimize the process of both charge transport and carrier dynamics in device system. In this research, materials used for photovoltaics device is ?c-SiOx:H for both p-type and n-type while a-SiOx:H has used for i-type layer. There are two configuration used in this study, the first one is ITO/graphene/(p-i-n)/Al and other one is ITO/(p-i-n)/graphene/Al. The first type is designed to boost charge carrier generation while the second type is to improve charge transport toward metal electrode (Al). In general, there are two models used in this simulation, single exponential method (SEM) and double exponential method (DEM) while for verification of the result, the method has compared with other experimental report from reference at specific case for EXPLOITATION OF GRAPHENE OPTOELECTRONICS PROPERTIES AS CARRIER BOOSTER LAYER AND EFFECTIVE CHARGES TRANSPORT MEDIUM IN THIN FILM ?c-SiOx:H BASED SOLAR CELLS device with (p-i-n) configuration using silicon as material based. Furthermore, the method has been developed for similar case where graphene has interfaces with (p-i-n) system under two type graphene/(p-i-n)/Al dan (p-i-n)/graphene/Al. In this research graphene layer thickness was varied from 0.4 to 2.0 nm according to experimental reference. Simulation result has shown that in first model the power conversion efficiency (PCE) at optimum condition reach 16.17% with short circuit current 30.86 mA/cm2 and carrier generation rate 65.31 x 1021/s at 0.67 nm graphene thickness while for conventional device the PCE has reach 11.31% with short circuit current 23.01 mA/cm2 and carrier generation rate 48.27 ×1021/s. For the second model (graphene thickness 0.67 nm called optimum condition) the efficiency reached 18.47% with short circuit current 34.59 mA/cm2 while for conventional device the efficiency reached 14.34% with short circuit current 27.85 mA/cm2. Series resistance for second model device with and without graphene is 18.22 ??/cm2 and 14.64 ??/cm2 respectively. Simulation taking into account result has shown that both carrier generation as well as transport properties are depend not only on thickness but also geometrical missmatch (GM) which is contribute to optical transmission and electronic transport. On the other hand, even the number or graphene layer can be controlled but geometrical missmatch is not easy to be controlled too when it experimentally synthesized so that fewlayer graphene (FLG) is highly potential to result in different properties among other even they have similar number of layer. According to this simulation as obviously discussed before that the existence of graphene inside solar cells device able to boost carrier production more compared with without graphene involvement. In addition, the series resistance as one of the parasitic factor which become inhibits charges transport mobility is also reduced. This obviously shown that graphene takes a role as booster carrier as well as charge transport medium layer and also reduce interfacial problem with electrode.