Recent Developments in Solar Cell Materials

RECENT DEVELOPMENTS IN SOLAR CELL MATERIALS

A typical solar cell consists of semiconducting materials such as p- and n-type silicon. In order to achieve maximum solar-to-electricity efficiency, innovative solar energy materials, at low cost, are being used.

1. Types of highly investigated solar cell materials

Some types of highly investigated semiconducting materials now used are

1. Crystalline Si

2. Thin films

3. Next generation Perovskite Solar Cells (PSCs)

4. Solar paints

5. Transparent solar windows

6. Thermoradiative PV devices

7. Solar distillation

1. Crystalline silicon (c-Si)

Crystalline silicon (c-Si) is the most used (90% of the global PV market) semiconducting material in solar panels. But, its efficiency is only 30%. So, solar cells with low-cost and high-efficiency materials are emerging.

Examples

(i) III-V multijunction materials: (efficiency > 30%)

(ii) Hybrid tandem III-V/Si solar cells: (efficiency > 30%)

(iii) Six-junction III-V solar cells under concentrated light (efficiency > 47.1%)

(iv) Si-based bifacial technology: (efficiency is 11% more compared to standard panels)

2. Thin films

Due to their narrow design (light weight, flexibility and ease of installation) second-generation thin-film solar cells are growing as one of the most promising PV technologies. This films are 350 times smaller light absorbing layers compared to standard Si-panels.

Examples

(i) Cadmium-telluride (CdTe).

(ii) Amorphous silicon.

(iii) Gallium - arsenide (GaAs).

(iv) Copper - Indium - Gallium - Selenide (CIGS).

Of all, CIGS is the more efficient with efficiency upto 21%.

3. Perovskite solar cells

Among the next generation solar cells, hybrid metal halide perovskite solar cells (PSCs), play an important role due to their low price, thinner design, low temperature processing and excellent light absorption properties.

Examples

Combined perovskite and Si-PV materials shows a record efficiency of upto 28%.

4. Solar paints

Solar paint is the another transformative technology. These can be coated over the polymer films.

Examples

(i) Solar paint hydrogen generates energy from photovoltaic water splitting

(ii) Quantum dots (Photovoltaic paint)

(iii) Perovskite - based paints

5. Transparent solar windows

They possess highly innovative applications. Their solar-to-electricity conversion efficiency is 10% more.

6. Thermoradiative PV devices (or) Reverse solar panels

They can generate electricity at night by utilizing the heat irradiated from the panels to the optically coupled deep space, which serves as a heat sink.

Fig. 7.10 Thermoradiative PV devices

7. Solar distillation

It can harvest solar energy while utilizing the dissipated heat from panels to purify water, if there is an integrated membrane distillation attachment.