A solar cell  is an electronic device which directly converts sunlight into electricity. Light shining on the solar cell produces both a current and a voltage to generate electric power. This process requires firstly, a material in which the absorption of light raises an electron to a higher energy state, and secondly, the movement of this higher energy electron from the solar cell into an external circuit. The electron then dissipates its energy in the external circuit and returns to the solar cell. A variety of materials and processes can potentially satisfy the requirements for photovoltaic energy conversion, but in practice nearly all.

2. Inorganic Bottom Solar Cell

 The core technology of tandem SCs

1. High efficiency top and bottom solar cell.

2. Efficient tunnel junction layer.

3. No less transparent conductive oxide on top solar cell.

 Why c-Si based approach tandem solar cells ?

1. To make the PV modules with higher efficiency.

2. c-Silicon solar cells is market leading solar cell.

3. The top cell in silicon based tandem should have a band gap between 1.6eV and 1.9eV.

    It leads to over a Shockley Quessier limit.

1. Inorganic/ Organic Hybrid Tandom Solar Cell

- P-type Silicon Based Solar Cell

- N-type Silicon Based Solar Cell

Perovskite/ Silicon

3. The main technology of Tandom Solar Cell

DSSC/ Silicon

 Rear contact solar cells eliminate shading losses altogether by putting both contacts on the rear of the cell. By using a thin solar cell made from high quality material, electron-hole pairs generated by light that is absorbed at the front surface can still be collected at the rear of the cell. Such cells are especially useful in concentrator applications where the effect of cell series resistance is greater.

 An additional benefit is that cells with both contacts on the rear are easier to interconnect and can be placed closer together in the module since there is no need for a space between the cells.

Passivated Emitter Rear Cell

Standard Solar Cells

Interdigitated Back Contact Solar Cells (IBC)

The photovoltaic characteristics of SiNWs/PEDOT:PSS hybrid solar cells prepared with different nanowire length under AM1.5 illumination condition. SEM images of the PEDOT:PSS covered SiNWs with different etching time (a) 1m (b) 2m (c) 4m (d) 8m

(a)-(d) The cross-sectional FE-SEM images of nanowires with different length. The nanowire length is approximately (a) 400, (b) 800, (c) 1600 and (d) 3200, respectively.


Experimental Process

 Inorganic/organic hybrid solar cells that combine n-type silicon nanowires (SiNWs) with poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonate) (PEDOT:PSS) have great potential for replacing commercial Si solar cells.

The main advantage of SiNWs is that they show greater light absorption (minimal reflectivity) due to incident light-trapping within the NW arrays. In addition, PEDOT : PSS based hybrid solar cells have been actively studied due to high power conversion efficiency, low material cost, low temperature and simple solution based process capability.

Why PEDOT : PSS / Si nanowire hybrid solar cells?

4. Inorganic/ Organic Hybrid Tandom Solar Cell

Efficiency of the polymer embedded silicon MWs Solar Cell

Transparency of the polymer embedded silicon MWs

PDMS/ Silicon microwires composite film

 Transparent solar cells have high potential for application to many fields such as building integrated photovoltaics (BIPV) and integrated photovoltaic chargers for portable electronics. For example, if transparent solar cells are placed on windows in a building, energy savings can be accomplished from the heat shielding and the transformation of solar light to produce electricity. If glass windows in one building were replaced with transparent solar cells, its electricity consumption could drop by approximately 10%. Therefore, the market outlook for BIPV is positive, and market size is expected to dramatically increase. In this current trend of transparent solar cells, many academic studies have been conducted in this field.

6. Transparent Solar Cell

5. Photo-Ferroic Solar Cell

 Ferroelectric materials which have spontaneous electric polarization are widely used as memory storage devices, field effect transistors and random access memories due to its excellent polarization switching property. In the efficiency point of view, traditional ferroelectric based PV devices, ferroelectric materials have a key role to absorption light and dissociate electron-hole pair as an active layer. Recently, new strategy to take advantage of ferroelectric layer as interfacial layer has been developed. This process could enhance the internal electric field of a p-n junction and lead to increased Voc in organic solar cells. We suggest novel and simple method for fabricating porous P(VDF-TrFE) thin film with highly controllable and reproducible approach. Porous P(VDF-TrFE) thin film which have excellent ferroelectric property applied to new PV device concepts composed of PEODT:PSS/P(VDF-TrFE)/Si.