Quantum Dots for Photovoltaic Cells with Tunable Absorption Spectrum

Topics Covered

Introduction - CANdots Nanoparticles
Production Process
Applications of CANdots Nanoparticles
About Strem Chemicals

Introduction - CANdots Nanoparticles

Leveraging its knowledge in nanoparticle synthesis and ligand modification, CAN GmbH develops optimized particles for optoelectronic devices, such as CANdots Series C (Figure 1) for use in solar cells. The CANdots Series C particles exhibit a tunable absorption edge by altering their size. This, in turn, allows their absorption spectrum to fit to the solar profile (Figure 2).

Figure 1. CANdots Series C nanoparticles

Figure 2. Comparison of solar radiation and absorption spectrum of CANdots Series C

A TEM image of CANdots Series C nanoparticles is depicted in Figure 3. Figure 4 shows the emission spectra of CANdots Series C nanoparticles having a diameter range of 3-7nm.

Figure 3. TEM image of CANdots Series C particles

Figure 4. Emission spectra of CANdots Series C nanoparticles with diameters from 3 to 7 nm

Production Process

A patent pending continuous flow process enables manufacturing larger quantities of CANdots nanoparticles at an unprecedented low cost. Furthermore, this method ascertains a high reproducibility of all particle properties at each production volume. This, in turn, yields higher quality materials when compared to products manufactured by batch syntheses.

Applications of CANdots Nanoparticles

CANdots nanoparticles exhibit a narrow size distribution, making them suitable for producing thin films comprising defined monolayers by means of different coating methods. Different customization steps are required to apply semiconductor nanoparticles as absorber material in solar cells for optimized processability and performance. Hence, other than standard product, further customization steps are offered by CAN GmbH to improve the value of customer applications.

CANdots Series A nanoparticles can also be applied for photovoltaic purposes. With fluorescence and absorption in the visible, these materials are ideal for use in niche applications or facilitating quality control, for instance in film preparation. The following table provides the characteristics of CANdots Series A and CANdots Series C nanoparticles.

CANdots® Series A
Material semiconductor nanoparticles (CdSe-based)
Dispersibility organic solvents (usually hexanes)
Absorption edge 480 to 610 nm (2.0 to 2.6 eV)
Emission wavelength 500 to 625 nm (2.0 to 2.5 eV)
CANdots® Series C
Material semiconductor nanoparticles (PbS-based)
Dispersibility organic solvents (usually toluene)
Absorption edge 880 to 1500 nm (0.8 to 1.4 eV)
Emission wavelength 1000 to 1600 nm (0.8 to 1.2 eV)

About Strem Chemicals

Strem Chemicals, Inc. established in 1964, is a privately-held company that manufactures and markets specialty chemicals of high purity. Its clients include academic, industrial and government research and development laboratories as well as commercial scale businesses in the pharmaceutical, microelectronic and chemical / petrochemical industries. Strem Chemicals also provides custom synthesis and cGMP manufacturing services.

Strem Chemicals' corporate headquarters is located in Newburyport 38 miles (60km) north of Boston. In 1999 this site was expanded to 30,000 sq. ft (2,800 m2). Its cGMP facility is FDA inspected. The European headquarters and warehouse are located in Bischheim, France.

Strem Chemicals, Inc. is a member of SOCMA (Synthetic Organic Chemical Manufacturers Association) and is committed to Responsible Care®.

Our mission is to provide specialty chemicals of high purity, in a timely fashion, to help our customers achieve their research and development and commercial objectives."

"We recognize that the successful growth of our organization is the result of a synergy that utilizes the talents and teamwork of our employees, suppliers and customers."

"Our employees are committed to personal integrity, cooperative effort and mutual respect and are empowered to take an active role to provide great customer service."

This information has been sourced, reviewed and adapted from materials provided by Strem Chemicals.

For more information on this source, please visit Strem Chemicals.

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