  Photovoltaic cells (PVc), as an energy provider to the next generation and
the biggest source of renewable energy. Since the last decade improving
efficiency and reducing the cost of PVc has been a subject of active research
among scientists. Promising progress in the field of material science and
manufacturing process at Nano-level played a big role. Still, at present there
are many challenges before photovoltaics for efficient and economic energy.
However, Photovoltaics cell based on p-n type homojunction semiconductors with
different organic and inorganic materials reported thus for generally suffer
from poor performance. According to the available literature, colloidal quantum
dots having immense properties like a wide range of light absorption, easily
charge separation and transport. To utilize the maximum part of the spectrum of
solar energy reaching to the earth and making effective energy production, here
we introduce the complete cell architecture and numerical investigation on
quantum dot based solar cells (QDSCs) with a heterostructure multijunction
approach. Successive ionic layer adsorption at different heterogeneous
interfaces were analyzed. We majorly focused on improving the electrical and
optical properties of the QDSCs achieved by different materials and structural
approaches. Here, we report a heterostructure II-Type of band alignment
engineering strategy for QDSCs interfaces that significantly enhances the
efficiency descriptors. In the context of intermediate band solar cell (IBSC),
we investigated optical properties of QDs and strain effects on multilayer PVc
and we summarize the strain effect in QDs growth and local energy band bending
of conduction band (CB) and valence band (VB).
