Contents lists available at ScienceDirect Optics Communications journal homepage: www.elsevier.com/locate/optcom Improvement of photon management in partial rear contact solar cells using a combination of DBR and Mie scatterers Suchismita Mitra a , Hemanta Ghosh a , Hiranmay Saha a , Swapan Kumar Datta a , Partha Chaudhuri a, ⁎ , Chandan Banerjee b a Centre of Excellence for Green Energy and Sensor Systems, Indian Institute of Engineering Science & Technology, Shibpur, Howrah 711103, India b National Institute of Solar Energy, GwalPahari, Haryana, India ARTICLE INFO Keywords: Thin silicon solar cells Distributed Bragg reflector Backscattering Mie scattering Silica nanoparticle ABSTRACT In this article, we present systematic simulations and numerical analysis of a novel light trapping scheme in a partial rear contact (PRC) solar cell involving a combined effect of rear located Distributed Bragg Reflectors (DBRs) and Mie scatterers comprising of dielectric nanoparticles (DNP), thereby, enhancing the efficiency of the device. We have studied the effect of three different types of DBRs in combination with embedded silica (SiO 2 ) DNPs which scatter light into silicon substrate of PRC c-Si solar cell. The materials for DBRs are chosen in such a way that they may serve the dual purpose of reflecting more than 90% of incident light at the rear surface and passivating it as well. The internal reflection from the rear surface, absorption enhancement ratio and average scattering angle have been computed from 3-dimensional finite difference time domain (FDTD) simulations and performing numerical analysis later on. Further, these results are used in the analysis of basic solar cell to extract the parameters like short circuit current density, open circuit voltage, fill factor, reverse saturation current density and efficiency of solar cell. It has been observed that significant increase in efficiency can be achieved for solar cells having 10–100 μm thick substrates by incorporating this light trapping scheme. Beyond 100 μm thickness, the conversion efficiency approaches a saturation value. Moreover, a combination of DBR with silica nanoparticles results in maximum efficiency near 50 μm thickness of solar cell thereby improving the baseline efficiency from ~20.3% to an absolute value of 22.9%. This study opens up a new perspective of light management using the advantages of highly reflective DBRs and highly scattering DNPs which can be incorporated in a rather simple and inexpensive way for thin ( < 100 μm) silicon solar cells. 1. Introduction Recent trend towards achieving high efficiency c-Si solar cells involves formation of partial rear contacts (PRC) where only a fraction of rear surface is covered with metal while the remaining fraction is passivated with a dielectric layer. Such rear-contact scheme is generally adopted by passivated emitter-rear contact (PERC) and passivated emitter-rear locally diffused (PERL) solar cells [1]. It offers low effective rear-surface recombination velocities as metallization fraction is reduced compared to full rear metal contact. But internal reflection from the rear surface suffers as the aluminium-silicon interface reflects only 65–70% of the incident light at the rear surface. Thus, effective light trapping schemes become a pre-requisite for achieving high efficiency in c-Si solar cells using the PRC scheme, especially for thin substrates as c-Si exhibits low absorption coefficients in the high wavelength range i.e in red and near infrared region. One of the most common strategies of light management is absorption enhancement where random textured surface and back metal reflectors have been commonly used [2,3]. Investigations suggest that internal back reflec- tance of c-Si solar cells can be improved by using rear side dielectric stacks [4]. Apart from these, implementation of 1D, 2D and 3D photonic crystals have also been proposed to enhance light trapping [5–7]. Similarly, improvement in efficiency owing to light trapping due to a photonic structure in a polymeric solar cell has also been demonstrated [8]. Another approach to improve light absorption is the use of highly reflective ( > 95%) one-dimensional Distributed Bragg Reflectors (DBRs). A DBR structure is formed using multiple layers of alternate materials with different refractive indices. This results in periodic variation of effective refractive index in the DBR. The reflectivity of a DBR can be tuned in accordance to the desired wavelength range. Broadband back reflectors can be formed by using consecutive DBRs of http://dx.doi.org/10.1016/j.optcom.2017.03.070 Received 28 December 2016; Received in revised form 22 February 2017; Accepted 27 March 2017 ⁎ Corresponding author. E-mail address: partha.iacs@gmail.com (P. Chaudhuri). Optics Communications 397 (2017) 1–9 0030-4018/ © 2017 Published by Elsevier B.V. MARK