Product Briefing Outline: LOT Oriel has introduced the SPEQUEST a spectral response measurement system which incorporates a monochromatic light source. SPEQUEST also operates a QTH light source with a dual-grating Czerny Turner spectrograph to provide monochromatic light between 300 and 1700nm. For UV measurements below 300nm SPEQUEST can be upgraded with a xenon arc lamp to provide output down to 200nm.
Problem: In today’s rapidly evolving markets for solar cells, the characterisation of the spectral response (quantum efficiency) is one of the most important parameters for research and development of new materials and devices but also for production and quality control. Today still 90% of the solar cells manufactured around the world are single junction silicon devices; therefore the layout of a spectral response measurement system is relatively simple and straightforward. However, the most promising research areas focus on different devices and materials, e.g. thin film and 3rd generation devices, which require a different layout of a spectral response characterisation system.
Solution: SPEQUEST takes into account the latest developments in solar cell research, the modular and very flexible setup enables quick and simple adaptation to research and production requirements. Accurate quantum efficiency measurements of solar cells require a light source for biased characterization measurements. The standard SPEQUEST system comes with a white light bias lightsource, multicolour bias light sources are available as well. The electrical signal is fed into a Lock-In amplifier via a Melles Griot large range IV converter. Careful selection of the detection electronics and adaptation to the optical system ensures maximum measurement accuracy.
The superior stability of the QTH monochromatic light source allows a single Lock-In amplifier setup.
Applications: All type of solar cells: polysilicon, c-Si, mc-Si, nc-Si, III/V compound cells: thin film: CdTe, CIS, CIGS, Si, 3rd generation: organic polymer, dye. Single and multijunction devices Spectral range 200 – 2500nm. Variable bias light (white light or multicolour)
Platform: The standard vacuum stage allows easy sample mounting of solar cells and devices, electrical probing is done via standard PH100 Karl-Suess-Probes. For maximum accuracy the stage can be equipped with a temperature controller. PHOTOR software operates under Windows operating system, support of platforms like Linux and MacOS is currently under development. The algorithms used in PHOTOR meet all IEC standards for spectral response measurements.
Availability: Currently available.
