Oriel® Instruments IQE-200® takes 40 years of light source and monochromator expertise, as well as innovation in optical design to create a sophisticated measurement tool for Quantum Efficiency (EQE and IQE) with options that allow the user customize a solution that meets their needs for PV measurement. If your needs include a customization of the light delivery, mapping capability or other variation, please contact a Newport sales engineer to discuss custom configurations/capabilities.
Oriel Instrument's IQE-200 measurement systems allows researchers to measure External Quantum efficiency (EQE) also known as Incident Photon to Charge Carrier Efficiency (IPCE) as well as Internal Quantum Efficiency (IQE) for solar cells, detectors, or any other photon-to-charge converting device.
These systems utilize industry standard, durable Oriel components for the light management engines. Each model of the IQE-200 system provides a "turnkey" solution by providing the light source, monochromator, detectors, related electronics, software and PC in a preconfigured, assembled and calibrated format. A variety of accessory modules are available to provide positive sample positioning, temperature control, electrical probing capabilities and light bias. The IQE-200 incorporates a novel detector geometry which splits the beam allowing for simultaneous measurement of EQE and the reflective losses to quantify IQE. In addition, an accessory detector can be mounted which allows for measurement of Transmission through the cell for those samples on a transparent substrate. The unique design of the AC system meets the requirements outlined in ASTM Method E 1021-06, and ASTM Method E2236-05a
The IQE-200 accessories customize the system to perform QE measurements incorporating temperature control, light biasing, and even motorized mapping capabilities all controlled by our new QE Commander ™ software system. Customized software can allow the user to "map" the entire device under test by wavelength or by a user definable pattern.
All Oriel components are from Newport Corporation, an industry leader in light sources, spectroscopy products, precision motion control, and continuous wave solar simulators.
What are EQE and IQE?
External Quantum Efficiency (EQE) indicates the ratio of the number of photons incident on a solar cell to the number of generated charge carriers, while Internal Quantum Efficiency (IQE) considers the internal efficiency; that is, the losses associated with the photons reflected back from the surface of the cell are also measured to claculate a net efficiency.
The EQE/IQE measurements are critical especially during the materials research and cell design stage to understand the conversion efficiency as a function of the wavelength of light impingent on the cell. The matrix of the solar cells can be altered to optimize the performance of the cells for any given spectral component of the sunlight. The overall efficiency of the cells can be optimized so conversion occurs over a broader spectrum of light, increasing overall performance efficiency of the cell.
QE Applications matrix for Solar Cells
- AC Measurement performed according to ASTM E 1021-06
- AC Measurement performed according to ASTM E 2236-05a
- All types cells
- AC method is preferred where light biasing* is needed
- Voltage Biasing capable with external voltage source (not included)
- Multi juction cells using the optional IQE-Light Bias kit with appropriate filters
- Si based cells amorphous and mono / poly crystalline
- Thin Film cells
- CIGS (copper indium gallium diselenide)
- CdTe (cadmium telluride)
- DSSC cells at very slow chopper speed where white light bias is needed to excite the cell
- Tandem/Multi Junction Cells
- A-Si based cells alloyed with Ge, C, O, and N
- Light biasing option with filters needed to saturate junction not under test
- Light bias source with adjustable intensity level
- Color filter(s) needed to DC bias each layer not being tested
* Colored filters are available for biasing a junction
Built by Newport Corporation's, Oriel Instruments, an industry leader in light sources and spectroscopy, so you can rely on our expertise to ensure the accuracy of the measurement
Product Detail
To accurately measure the EQE/IQE of a solar cell the system calculates the ratio of current produced by the monochromatic light at a given wavelength to the current generated by reference detectors at the same wavelength. The unique optical design of the IQE-200 allows for simultaneous measurement of the sample, reference detector and a second reference detector for reflected light to produce a precise measurement of EQE and IQE simultaneously without repositioning detectors or sample. The monochromator used is configured with the appropriate gratings for the wavelength range of the detector system. Order sorting filters have been chosen and preinstalled specific to the wavelength range of each model.
The IQE-200 utilizes a modular design concept which allows for flexibility in light source (QTH or Xenon), a 1/8 m monochromator, order sorting filters in a motorized filter wheel, chopper motor with lock-in amplifier, and detector choices for desired wavelength ranges to create a flexible platform for AC type measurements of solar cells.
Typical Light AC Engine configuration
- Light source – Can be ordered with a 250 W Quartz Tungsten Halogen (QTH) Source or a 150W Xenon Arc lamp. The light source is coupled to a monochromator to create the scanning monochromatic light.
- The 1/8m Monochromator provides excellent throughput and resolution and is controlled via USB connection through the QE Commander software.
- Gratings have been chosen to optimize performance for the entire wavelength range of interest.
- An automated filter wheel with appropriate order sorting filters is incorporated to minimize second order artifacts and are specific to the wavelength range defined by the detectors in use.
- Merlin lock-in amplifier, optical chopper and calibrated detectors.
- A single channel lock-in amplifier is along with a four channel multiplexer to measure up to four channels during a run. The lock-in amplifier comes with a built-in chopper controller. An optical chopper with one two-aperture blade is also included in the kit.
Typical Detection Configuration
- Uses Calibrated detectors
- (1) reference detector
- (1) reference detector for measuring reflected light
- (1) optional detector for measuring transmitted light
- Output optics are downward looking and focus to a 1 x 2.5mm spot size at the focal plane (Speak to your sales engineer for upward or side looking output)
- Light Bias Preamp designed to interface a current generating device to work with the Merlin Digital Lock-in Amplifier under light biasing or electrical biasing conditions.
Optional Accessories Available:
- Temperature Controlled Vacuum Chuck* (IQE-TC-VAC)
- *Water Bath/Chiller and Vacuum pump ordered separately)
- Temperature controlled circulating water bath (PVIV-CHILLER)
- Electrical Contact probes ( PVIV-PROBE-KIT)
- Vacuum pump (PVIV-VAC-PUMP)
- Light Biasing kit to deliver white or colored biasing illumination (IQE-LIGHT-BIAS)
Temperature Controlled Vacuum Chuck with Electrical Probes
Chiller
Vacuum Pump
Light Bias Kit with Optional Filters
Software
The Oriel QE Commander software is written using LabView® and comes pre-installed on a laptop computer included as part of the system. The QE Commander software provides control of the hardware via a simple intuitive interface allowing for one button data acquisition for EQE and IQE. QE COmmander can be customized to allow the user to create a map of QE performance over a user defined area or pattern of the device under test. Your Newport sales engineer can discuss the hardware requirements and customization of the QE Commander software to fit your application (additional costs may apply for application development).
QE Commander controls all the basic system components, including the monochromator, order sorting filter wheel, Merlin lock-in amplifier, chopper and light source power supply. It is also designed to control the Oriel accessory light biasing source, chiller for the temperature controlled vacuum chuck and motion controllers for mapping. QE Commander measures up to 4 channels in a single pass and generates real time EQE and IQE curves as a fuction of wavelength being measured. It can provide real time readout of temperature and ISc as well. EQE and IQE are all calculated in a single pass without the need to reposition detectors or sample, minimizing error in measurement accuracy.
The IQE-200 models and QE Commander software offer a versatile design which allows for customization of the sytem configuration and software to suit many applications. Please contact a Newport sales engineer to discuss your application for a quotation on a system that meets your applications specific needs.
