This technical report discusses the terminology and the measuring methods of optoelectronic efficiencies of single light emitting diode (LED) chip or package without phosphor. White LEDs for lighting applications are out of the scope of this part.<\/p>\n
This technical report provides guidance on<\/p>\n
terminology of optoelectronic efficiencies of single LED chip or package without phosphor, such as the power efficiency (PE), the external quantum efficiency (EQE), the voltage efficiency (VE), the light extraction efficiency (LEE), the internal quantum efficiency (IQE), the injection efficiency (IE), and the radiative efficiency (RE) [1]1<\/sup>;<\/p>\n<\/li>\n test methods of optoelectronic efficiencies of the PE, the EQE, the VE, the LEE, and the IQE [1];<\/p>\n<\/li>\n review of various IQE measurement methods reported so far in view of accuracy and practical applicability;<\/p>\n<\/li>\n the measuring method of the LED IQE based on the temperature-dependent electroluminescence (TDEL) [2];<\/p>\n<\/li>\n the measuring method of the LED IQE based on the room-temperature reference-point method (RTRM) [3];<\/p>\n<\/li>\n the measuring method of the radiative and nonradiative currents of an LED [4];<\/p>\n<\/li>\n the relationship between the IQE and the VE, which leads to introduction of a new LED efficiency, the active efficiency (AE) as AE = VE \u00d7 IQE.<\/p>\n<\/li>\n<\/ul>\n Semiconductor devices – Optoelectronic devices. Light emitting diodes. Test method of LED efficiencies<\/b><\/p>\nPDF Catalog<\/h4>\n
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\n PDF Pages<\/th>\n PDF Title<\/th>\n<\/tr>\n \n 2<\/td>\n undefined <\/td>\n<\/tr>\n \n 4<\/td>\n CONTENTS <\/td>\n<\/tr>\n \n 7<\/td>\n FOREWORD <\/td>\n<\/tr>\n \n 9<\/td>\n INTRODUCTION <\/td>\n<\/tr>\n \n 10<\/td>\n 1 Scope
2 Normative reference
3 Terms and definitions <\/td>\n<\/tr>\n\n 11<\/td>\n 3.1 General terms and definitions
3.2 Terms and definitions relating to the optoelectronic efficiencies <\/td>\n<\/tr>\n\n 13<\/td>\n 3.3 Terms and definitions relating to measuring the efficiencies <\/td>\n<\/tr>\n \n 14<\/td>\n 3.4 Terms and definitions relating to measuring current components
3.5 Abbreviated terms <\/td>\n<\/tr>\n\n 15<\/td>\n 4 LED efficiencies
4.1 General <\/td>\n<\/tr>\n\n 16<\/td>\n Tables
Table 1 \u2013 LED items and their measuring methods listed in IEC 60747-5-6:2016 <\/td>\n<\/tr>\n\n 17<\/td>\n 4.2 Theoretical background of optoelectronic efficiencies <\/td>\n<\/tr>\n \n 21<\/td>\n Table 2 \u2013 Summary of efficiency items defined in IEC 60747-5-8:2019 <\/td>\n<\/tr>\n \n 22<\/td>\n 4.3 Separate measurement of various efficiencies
4.4 Requirements for accurate and reliable IQE measurement
Figures
Figure 1 \u2013 Sequence of the efficiency measurements <\/td>\n<\/tr>\n\n 23<\/td>\n 4.5 Classification of IQE measurement methods <\/td>\n<\/tr>\n \n 24<\/td>\n 5 Conventional IQE measurement methods: features and limitations
5.1 Calculation of the LEE
5.2 Temperature-dependent photoluminescence (TDPL)
Table 3 \u2013 Various LED IQE measurement methods <\/td>\n<\/tr>\n\n 25<\/td>\n 5.3 Intensity-dependent photoluminescence (IDPL) or simply photoluminescence (PL) <\/td>\n<\/tr>\n \n 28<\/td>\n 5.4 Temperature-dependent time-resolved photoluminescence (TD-TRPL) <\/td>\n<\/tr>\n \n 30<\/td>\n 5.5 Time-resolved photoluminescence (TRPL) <\/td>\n<\/tr>\n \n 32<\/td>\n Figure 2 \u2013 Theoretical model for analysing the TRPL experiment <\/td>\n<\/tr>\n \n 34<\/td>\n Figure 3 \u2013 Schematic TRPL response and its interpretation in terms of various lifetimes <\/td>\n<\/tr>\n \n 35<\/td>\n Figure 4 \u2013 Temporal responses of the TRPL for three samples <\/td>\n<\/tr>\n \n 36<\/td>\n 5.6 Time-resolved electroluminescence (TREL)
Figure 5 \u2013 Fitted results of the measured TRPL response <\/td>\n<\/tr>\n\n 37<\/td>\n Figure 6 \u2013 Schematic diagram of the pulse current injection <\/td>\n<\/tr>\n \n 41<\/td>\n 5.7 Constant ABC model
Figure 7 \u2013 Square of as a function of current density for a bias voltage
Figure 8 \u2013 Estimated IQE (left axis) and measured EQE (right axis) versus current density <\/td>\n<\/tr>\n\n 44<\/td>\n Figure 9 \u2013 Experimental EQE curve of a blue LED
Figure 10 \u2013 Normalized EQE curves (solid lines) and experimental data (rectangular symbols) for different IQE peak values as a parameter for a blue LED emitting at 460 nm <\/td>\n<\/tr>\n\n 45<\/td>\n Figure 11 \u2013 SRH nonradiative carrier lifetime tsRH ((= 1\/A) as a function of the coefficient calculated from Equation (82)
Figure 12 \u2013 Experimental EQE curve of a blue LED <\/td>\n<\/tr>\n\n 47<\/td>\n 5.8 Constant AB model <\/td>\n<\/tr>\n \n 48<\/td>\n 6 Standard IQE measurement method I: TDEL
6.1 Temperature-dependent electroluminescence (TDEL) method
6.2 Temperature-dependent radiant power <\/td>\n<\/tr>\n\n 49<\/td>\n 6.3 Evaluation of the IQE
Figure 13 \u2013 Temperature characteristics of an LED <\/td>\n<\/tr>\n\n 51<\/td>\n 6.4 Validity of the TDEL: examples of blue LEDs
Figure 14 \u2013 IQEs as a function of current at various operating temperatures from room to cryogenic measured by the TDEL method <\/td>\n<\/tr>\n\n 52<\/td>\n 6.5 Sequence of IQE determination by the TDEL
Figure 15 \u2013 Two different cases of normalized EQE curves as a function of current at various temperatures <\/td>\n<\/tr>\n\n 53<\/td>\n 6.6 Summary of the TDEL
7 Standard IQE measurement method II: RTRM
7.1 Room-temperature reference-point method (RTRM)
Figure 16 \u2013 Sequence of the IQE measurement by the TDEL method <\/td>\n<\/tr>\n\n 54<\/td>\n 7.2 Recombination coefficients, A, B, and C in semiconductors <\/td>\n<\/tr>\n \n 55<\/td>\n 7.3 Strategy of the IQE measurement just at an operating temperature <\/td>\n<\/tr>\n \n 56<\/td>\n 7.4 Theoretical background of the RTRM
Figure 17 \u2013 Comparison between the conventional ABC model and the improved AB model
Figure 18 \u2013 Calculation procedure from a relative EQE curve to an IQE curve with the RTRM <\/td>\n<\/tr>\n\n 58<\/td>\n 7.5 Example of the RTRM <\/td>\n<\/tr>\n \n 59<\/td>\n Figure 19 \u2013 IQE calculation procedure as a function of current based on the RTRM <\/td>\n<\/tr>\n \n 61<\/td>\n 7.6 Comparison of IQEs by the TDEL and the RTRM
Figure 20 \u2013 Example of the IQE calculation based on the RTRM <\/td>\n<\/tr>\n\n 62<\/td>\n 7.7 Summary of the RTRM
8 The RTRM versus the TDEL and the constant ABC model: comparisons
Figure 21 \u2013 Comparison of the IQEs evaluated by (a) the TDEL and (b) the RTRM <\/td>\n<\/tr>\n\n 63<\/td>\n Figure 22 \u2013 Radiant power versus current of a blue LED sample measured at various temperatures <\/td>\n<\/tr>\n \n 64<\/td>\n Figure 23 \u2013 Normalized intensities on linear and log scalesmeasured at various temperatures <\/td>\n<\/tr>\n \n 65<\/td>\n Figure 24 \u2013 I-V characteristics at various temperatures <\/td>\n<\/tr>\n \n 66<\/td>\n Figure 25 \u2013 Calculated a2 as a function of current for various temperatures. Iref at 300 K is the current giving the minimum value of a2 in region II.
Figure 26 \u2013 IQEs obtained by the RTRM (symbols) and the TDEL (solid lines) at various temperatures <\/td>\n<\/tr>\n\n 67<\/td>\n Figure 27 \u2013 Comparison of the IE obtained from a2 at 300 K (left axis) and the theoretical IE for constant Ileak (right axis) <\/td>\n<\/tr>\n \n 68<\/td>\n Figure 28 \u2013 Normalized EQE and the fitting by the constant ABC model
Figure 29 \u2013 Ratio of the SRH, radiative, Auger recombination currents to the total current <\/td>\n<\/tr>\n\n 69<\/td>\n 9 LED performance issues related to the IQE measurement
9.1 Various LED efficiency measurement <\/td>\n<\/tr>\n\n 70<\/td>\n Figure 30 \u2013 Radiant power and forward voltage as a function of forward current <\/td>\n<\/tr>\n \n 71<\/td>\n Figure 31 \u2013 Calculation of the mean photon energy from the emission spectra <\/td>\n<\/tr>\n \n 72<\/td>\n 9.2 Radiative and nonradiative currents
Figure 32 \u2013 LED efficiencies as a function of forward current <\/td>\n<\/tr>\n\n 74<\/td>\n Figure 33 \u2013 Sequence of the radiative and nonradiative current measurements
Figure 34 \u2013 IQE and forward voltage as a function of forward current <\/td>\n<\/tr>\n\n 75<\/td>\n Figure 35 \u2013 Radiative current and forward voltage as a function of forward current
Figure 36 \u2013 Nonradiative current and forward voltage as a function of forward current <\/td>\n<\/tr>\n\n 76<\/td>\n 9.3 The active efficiency (AE): IQE versus forward voltage
Figure 37 \u2013 Total forward current, radiative current, and nonradiative current plotted as a function of forward voltage <\/td>\n<\/tr>\n\n 78<\/td>\n Figure 38 \u2013 Distribution of the IQE and VF for 31 blue MQW LEDs <\/td>\n<\/tr>\n \n 79<\/td>\n Figure 39 \u2013 Optoelectronic characteristics of three samples under consideration
Table 4 \u2013 Parameters in IQE and current density versus voltage curves <\/td>\n<\/tr>\n\n 80<\/td>\n Figure 40 \u2013 Separated radiative and nonradiative current densities of samples 1 and 2 <\/td>\n<\/tr>\n \n 81<\/td>\n Figure 41 \u2013 Separated radiative and nonradiative current densities of samples 1 and 3
Table 5 \u2013 Comparison of recombination mechanisms between samples <\/td>\n<\/tr>\n\n 82<\/td>\n 10 Conclusion: test method of optoelectronic efficiencies of LEDs <\/td>\n<\/tr>\n \n 83<\/td>\n Bibliography <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":" \n\n
\n Published By<\/td>\n Publication Date<\/td>\n Number of Pages<\/td>\n<\/tr>\n \n BSI<\/b><\/a><\/td>\n 2021<\/td>\n 92<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"featured_media":422094,"template":"","meta":{"rank_math_lock_modified_date":false,"ep_exclude_from_search":false},"product_cat":[577,2641],"product_tag":[],"class_list":{"0":"post-422085","1":"product","2":"type-product","3":"status-publish","4":"has-post-thumbnail","6":"product_cat-31-080-99","7":"product_cat-bsi","9":"first","10":"instock","11":"sold-individually","12":"shipping-taxable","13":"purchasable","14":"product-type-simple"},"_links":{"self":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product\/422085","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/types\/product"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media\/422094"}],"wp:attachment":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media?parent=422085"}],"wp:term":[{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_cat?post=422085"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_tag?post=422085"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}