Glossary: Abbreviations, Terms and Definitions

AM-[ ] Active Matrix Flat-panel displays for laptop computers are created by laying diodes over a superfine grid of wires. The diodes are activated by applying current to various points around the grid. Connect enough of these dots and you get an image. Active-matrix displays use transistors to keep their diodes in an on or off state, unlike their passive-matrix cousins, which rely on the diodes' persistence. As a result, active-matrix displays are brighter and produce better colour than passive-matrix displays. However, the additional technology required to build active displays also makes them more expensive. calc calibration A process of adapting a sensor output to a known physical quantity to improve sensor output accuracy. CCD charged coupled device a semiconductor device in which generated electronic charge is accumulated and transferred by the application of electrical potentials to insulated electrodes or gates. The charge is generated by received photons. CE current efficiency Amount of visible radiation emitted divided by electrical current flowing through an OLED. CIE Commision Internationale de le Èclairage (International Commision on Illumination). A convenient way to specify a colour is by reference to a co-ordinate on a chromaticity diagram, one of the most frequently used was devised by C.I.E. in 1931. The reduced chromaticity co.ordinates (x,y) represent the hue and the saturation of the colour. CVD Chemical vapor deposition The most common thin film deposition method in advanced semiconductor manufacturing; deposited species are formed as a results of chemical reaction between gaseous reactants at elevated temperature in the vicinity of the substrate; solid product of the reaction is deposited on the surface of the substrate. DE Dopant material evaporator   Doping   Electrical doping of charge carrier transport layers in organic light emitting diodes using p-doping (hole transport - strong acceptor) and n-doping (electron transport - strong donor) EA electron affinity The energy released when an electron is added to an atom. If the electron affinity is negative, then energy is required to attach an electron to the atom EBL electron block layer this layer blocks electrons on the way to the emmiting layer EL electro- luminescence Physikal property of a material to emit light when biased with a voltage. EML emmiting layer in this layer electrons hit holes and emmiting light ETL electron transport layer this layer transport the electrons to the emmiting layer HBL hole block layer this layer blocks holes on the way to the emmiting layer HDTV High Definition Television The new 16:9 wide-format display technology that is currently being introduced. Provides brillant image due to its higher resolution compared to NTSC or PAL. HOMO highest occupied molecular orbital The energy of this orbital approximates the ionization energy of the molecule. HTL hole transport layer this layer transport the holes to the emmiting layer IL-E interlayer- elektron side Special layer in the unique Novaled OLED structure. This layer and the material it is made of is crucial for device performance and life-time. IL-H interlayer-hole side IP Intellectual Property legal entitlement concerning a process of the mind (e.g. patent rights) IP ionization potential The amount of energy required to remove an electron from a given molecule or atom to form an ion; usually expressed in units of electron volts. IR Infrared (radiation) electromagnetic radiation of a wavelength longer than that of visible light, but shorter than that of microwaves ITO indium-tin- oxid Electrically conducting transparent anorganic material widely employed in display technology to form the anode. L luminence Perceived brightness of a light emitting surface (e.g. display). LCD Liquid Crystal Display LCDs use two layers of polarizing material separated by a liquid crystal solution. An electric current passed through the liquid causes the crystals to align so that light cannot pass through them. Each crystal, controlled individually, acts like a shutter. Colour LCDs use two basic techniques for producing colour: Passive matrix is the less expensive, and active matrix, also called Thin Film Transistor (TFT), provides a sharper image. LCoS Liquid Crystal on Silicon AM Display built on crystalline Silicon substrate which results in smallest pixel sizes and highest resolutions. LCoS is used for microdisplays. LED Light Emitting Diode Light source that uses very little power and has a long life. Available as single colour red, green or yellow. If red, green and blue LEDs are used, it is also possible to display video. LIV- mea- sure- ment Light-Current- Voltage- measurement LUMO lowest unocupied molecular orbital The energy of this orbital is sometimes used to approximate the electron affinity of the molecule, but this usually works badly. ME Matrix material evaporator   nits Lumi- nescence defined as the emission of light from a substance in an electronically excited state. Depending on whether the excited state is singlet or triplet, the emission is called fluorescence (decay time about 10-8 seconds) or phosphorescence (longer than 10-3 second decay). Depending on the source, molecules get the needed extra energy from, different types of luminescence are distinguished: radioluminescence, photoluminescence (in the same category are fluorescence and phosphorescence), chemiluminescence and bioluminescence, electrochemiluminescence, sonochemi-luminescence and thermoluminescence. OEL Organic Electro- luminescent This is a generic term for organic light emitting devices typically fabricated from sublimed molecular films. This term is often used in Japan to describe variants of technology that originated with Kodak. OLED Organic light emitting diode The generic therm for Organic LED`s, which can be made from a wide range of organic materials, either small molecule or polymeric. PDA Personal Digital Assistant A very compact computer with functions such as scheduler, address book, etc. plus communications interfaces to PCs, mobile telephones and the internet. PDA photodiode preamplifier A linear array of discrete photodiodes on an integrated-circuit chip used in digital detection systems. PIN OLEDs   Novaled PIN OLEDTM technology  is a US trademark. PIN = P-doped, Intrinsic, N-doped Intentional electrical doping of hole and electron transport layers to improve charge carrier injection and transport. Pixel Picture Element The image shown on displays is made up of lots of small dots called pixels. Collectively, the number of pixels displayed is referred to as the image’s resolution. A pixel on a display in general consists of a number of red, green and blue sub-pixels. When all three sub-pixels are emitting, the pixel appears white to the human eye (from a certain distance). PL photo- lumines- cense The luminescence effect resulting from the stimulation of a material with visible IR or UV radiation. PM-[ ] Passiv Matrix These basic flat-panel displays are created by laying a layer of liquid-crystal diode elements or OLEDS between two crossed grids of wires. By applying current to the various intersections, the pixel/diodes can be lit. Passive displays simply apply current to the diodes at a specific refresh rate to maintain an image. Higher-quality (and, therefore, more expensive) active-matrix or TFT displays control each diode with one or more transistors, making for sharper, brighter pictures. p-Si Polycrystalline Silicon Amorphous silicon can be heat treated to increase silicon grain sizes by recrystallization. p-Si has higher elctron mobility than a-Si. PVD Physical vapor deposition Deposition of thin film occurs through physical transfer of material (e.g. thermal evaporation and sputtering)from the source to the substrate; chemical composition of deposited material is not altered in the process. Q.E. quantum efficiency The ratio of the number of quanta of radiant energy (photons) emitted per second to the number of electrons flowing per second. QCM Quartz crystal microbalance A piezoelectric quartz crystal is used to determine mass changes as a result of frequency change of the crystal. Material is coated onto the crystal that attracts a certain other material. When this other material becomes attached, it lowers the crystal frequency, the amount being directly related to its mass. The mass change can be in the nanogram range. R&D Research and Development   res resolution The smallest measurable change in input that will produce a small but noticeable change in the output. In the context of chemical separations, defines the completeness of separation. RGB Red, Green, Blue The usual pixel triads for emissive light reproduction of full colour images. RMS root mean square value for the roughness of a surface RT room temperature   TFD Thin Film Diode Potentially cheaper alternative method to realize active matrix driving. TFT thin film transistor A transistor formed from thin films of materials that are sequentially deposited on a substrate. The active layers of these devices are typically made with a multiple-crystal structure. Their performance is much lower than that of a single crystal transistor UHV ultra high vacuum Typically defined as pressures less tat 10-9 torr of gas. Such vacuum conditions are necessary for deposition techniques like PVD and CVD. UPS ultraviolet photoelectron spectroscopy This is a form of spectroscopy which measures the kinetic energy of electrons emitted from a sample when it is irradiated with high energy ultraviolet radiation. UV ultraviolet   V driving Voltage Potential difference between two points: energy to move a 1-C charge through a 1-V potential difference is 1-J. VIS visible Region of the electromagnetic spectrum that can be perceived by the human eye. It enfolds the wavelengths between 380 and 780 nm. XPS X-ray photoelectron spectroscopy Technique for determining the elemental composition at a solid surface by measuring the energy of electrons emitted in response to X-rays of different frequency. Has been applied to solid-phase combinatorial chemistry by incorporating a tracer atom in the linker.