【原创】UV-VIS的检测器集锦

二极管阵列(DAD)检测器

Photodiode Array Detectors (PDA)
Introduction
A photodiode array (PDA) is a linear array of discrete photodiodes on an integrated circuit (IC) chip. For spectroscopy it is placed at the image plane of a spectrometer to allow a range of wavelengths to be detected simultaneously. In this regard it can be thought of as an electronic version of photographic film. Array detectors are especially useful for recording the full uv-vis absorption spectra of samples that are rapidly passing through a sample flow cell, such as in an HPLC detector.
PDAs work on the same principle as simple photovoltaic detectors.
Schematic of a PDA

Light creates electron-hole pairs and the electrons migrate to the nearest PIN junction. After a fixed integration time the charge at each element is sequentially read with solid-state circuitry to generate the detector response as a function of linear distance along the array. PDAs are available with 512, 1024, or 2048 elements with typical dimensions of ~ 25 ?m wide and 1-2 mm high.

Photodiode and Photovoltaic Detectors
Introduction
When a photon strikes a semiconductor, it can promote an electron from the valence band (filled orbitals) to the conduction band (unfilled orbitals) creating an electron(-) - hole(+) pair. The concentration of these electron-hole pairs is dependent on the amount of light striking the semiconductor, making the semiconductor suitable as an optical detector. There are two ways to monitor the concentration of electron-hole pairs. In photodiodes, a voltage bias is present and the concentration of light-induced electron-hole pairs determines the current through semiconductor. Photovoltaic detectors contain a p-n junction, that causes the electron-hole pairs to separate to produce a voltage that can be measured.
Schematic of semiconductor detector

Photodiode detectors are not as sensitive as PMTs but they are small and robust.
Wavelength range
Table 1: Wavelength range
Detector type    ( )

Si    0.2 - 1.1
Ge    0.4 - 1.8
InAs    1.0 - 3.8
InSb    1.0 - 7.0
InSb (77K)    1.0 - 5.6
HgCdTe (77K)    1.0 -25.0

Array-Detector Spectrophotometer
Introduction
Array-detector spectrophotometers allow rapid recording of absorption spectra. Dispersing the source light after it passes through a sample allows the use of an array detector to simultaneously record the transmitted light power at multiple wavelengths. There are a large number of applications where absorbance spectra must be recorded very quickly. Some examples include HPLC detection, process monitoring, and measurement of reaction kinetics.
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Instrumentation
These spectrometers use photodiode arrays (PDAs) or charge-coupled devices (CCDs) as the detector. The spectral range of these array detectors is typically 200 to 1000 nm. The light source is a continuum source such as a tungsten lamp. All wavelengths pass through the sample. The light is dispersed by a diffraction grating after the sample and the separated wavelengths fall on different pixels of the array detector. The resolution depends on the grating, spectrometer design, and pixel size, and is usually fixed for a given instrument. Besides allowing rapid spectral recording, these instruments are relatively small and robust. Portable spectrometers have been developed that use optical fibers to deliver light to and from a sample.
These instruments use only a single light beam, so a reference spectrum is recorded and stored in memory to produce transmittance or absorbance spectra after recording the sample spectrum.

光电倍增管 / InGaAs /Cooled PbS

光电二极管和光电倍增管,这两种我们这都有。。有台荧光的，担不是很清楚里面的检测器，因为它还没有坏过。。。

Instrumentation
These spectrometers use photodiode arrays (PDAs) or charge-coupled devices (CCDs) as the detector. The spectral range of these array detectors is typically 200 to 1000 nm. The light source is a continuum source such as a tungsten lamp. All wavelengths pass through the sample. The light is dispersed by a diffraction grating after the sample and the separated wavelengths fall on different pixels of the array detector. The resolution depends on the grating, spectrometer design, and pixel size, and is usually fixed for a given instrument. Besides allowing rapid spectral recording, these instruments are relatively small and robust. Portable spectrometers have been developed that use optical fibers to deliver light to and from a sample.
These instruments use only a single light beam, so a reference spectrum is recorded and stored in memory to produce transmittance or absorbance spectra after recording the sample spectrum.

还有CCD和PDA，比如便携式的紫外上用到的。

我用过光电二极管和二极管阵列的检测器,一般的紫外都用光电二极管,同一时间只能单波测定,二极管阵列比较特殊,它很全谱同时测量.